Exhibit 99.1

Calgary, October 27, 2011

Imperial Oil announces estimated third quarter financial and operating results

Bruce March, chairman, president and chief executive officer of Imperial Oil, commented:

“Imperial Oil’s earnings in the third quarter of 2011 were $859 million, up 106 percent or $441 million from 2010. Strong market conditions were captured by our solid operating performance in the Upstream, Downstream and Chemical sectors. Another record quarterly production at Cold Lake and higher production at Syncrude contributed to an oil-equivalent production increase of five percent over the third quarter of 2010. Less scheduled refinery downtime contributed to a significant improvement in Downstream earnings in the third quarter compared to the second quarter of 2011. Our consistent focus on operations excellence and production reliability in all areas of our business allows us to continue to advance our growth plans while sustaining performance in our base business.

Our company growth program remains robust with capital and exploration expenditures of $2,888 million year-to-date as we continue to invest at a record level to develop new supplies of energy to meet growing world demand. The capital spending was primarily directed to the construction of the Kearl project and also includes activity to advance the Nabiye expansion at Cold Lake. Our continued strong business performance allowed us to finance these investments largely by cash flow from operations.”

Imperial Oil is one of Canada’s largest corporations and a leading member of the country’s petroleum industry. The company is a major producer of crude oil and natural gas, Canada’s largest petroleum refiner, a key petrochemical producer and a leading marketer with a coast-to-coast supply network that includes about 1,850 retail service stations.

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Third quarter items of interest

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Third quarter 2011 vs. third quarter 2010

The company’s net income for the third quarter of 2011 was $859 million or $1.01 a share on a diluted basis, compared with $418 million or $0.49 a share for the same period last year.

Earnings in the third quarter were higher than the same quarter in 2010 primarily due to stronger industry refining margins of about $270 million, higher crude oil commodity prices of about $190 million, increased Cold Lake bitumen production of about $90 million and higher Syncrude volumes of about $45 million. These factors were partially offset by the unfavourable impacts of the foreign exchange effects of the stronger Canadian dollar of about $65 million, higher royalty costs of about $60 million and lower conventional crude oil volumes of about $35 million due to third-party pipeline reliability issues.

Upstream net income in the third quarter was $534 million, $186 million higher than the same period of 2010. Earnings benefited from higher crude oil commodity prices of about $190 million, increased Cold Lake bitumen production of about $90 million and higher Syncrude volumes of about $45 million. These factors were partially offset by higher royalty costs due to higher commodity prices of about $60 million, the foreign exchange effects of the stronger Canadian dollar of about $45 million and lower conventional crude oil volumes of about $35 million due to third-party pipeline reliability issues.

The average price of Brent crude oil in U.S. dollars, a common benchmark for Atlantic Basin oil markets, was $113.46 a barrel in the third quarter of 2011, up about 48 percent from the corresponding period last year. Increase in the average price of West Texas Intermediate (WTI) crude oil, a common benchmark for mid-continent North American oil markets, was limited to 17 percent due to the continued weakness in WTI crude oil markets. Increases in the company’s average realizations on sales of Canadian conventional crude oil and synthetic crude oil were in line with that of WTI. Increase in the company’s average bitumen realizations in Canadian dollars in the third quarter was two percent to $58.23 a barrel as the price spread between light crude oil and Cold Lake bitumen widened.

Gross production of Cold Lake bitumen averaged 162 thousand barrels a day and established a new production record in the third quarter. Cold Lake production was up 17 percent from 139 thousand barrels in the same quarter last year. Increased volumes were due to contributions from new wells steamed in 2010 and 2011, increased recoveries and the cyclic nature of production at Cold Lake.

The company’s share of Syncrude’s gross production in the third quarter was 75 thousand barrels a day, versus 66 thousand barrels in the third quarter of 2010. Higher production was primarily the result of improved operating reliability partially offset by planned maintenance activities which began in September 2011 and will be complete in the fourth quarter of 2011.

Gross production of conventional crude oil averaged 12 thousand barrels a day in the third quarter, down from 22 thousand barrels in the third quarter of 2010. Lower volumes were primarily due to the third-party pipeline unplanned downtime which caused significantly reduced production at the Norman Wells field.

Gross production of natural gas during the third quarter of 2011 was 252 million cubic feet a day, down from 284 million cubic feet in the same period last year. The lower production volume was primarily a result of natural reservoir decline.

Downstream net income was $272 million in the third quarter of 2011, compared with $69 million in the same period a year ago. Earnings increased primarily due to stronger industry refining margins of about $270 million partially offset by higher expenses of about $40 million mainly due to higher maintenance activities and the unfavourable effects of the stronger Canadian dollar of about $20 million. Refinery crude runs increased by 39 thousand barrels a day in the third quarter, following completion of planned maintenance activities in the prior quarter.

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Third quarter 2011 vs. third quarter 2010 (continued)

Chemical net income was $37 million in the third quarter, $14 million higher than the same quarter last year. Improved industry margins for intermediate products and lower costs due to lower planned maintenance activities were the main contributors to the increase.

Net income effects from Corporate and other were $16 million in the third quarter, compared with negative $22 million in the same period of 2010. Favourable effects were primarily due to lower share-based compensation charges.

Cash flow generated from operating activities was $1,658 million in the third quarter of 2011, an increase of $693 million from corresponding period in 2010. Higher cash flow was primarily due to higher earnings along with working capital effects.

Investing activities used net cash of $1,061 million in the third quarter, compared with $1,113 million in the same period of 2010. Additions to property, plant and equipment were $1,087 million in the third quarter, compared with $1,147 million during the same quarter 2010. For the Upstream segment, expenditures during the quarter were primarily directed towards the advancement of the Kearl initial development and Kearl expansion oil sands project. Other investments included advancing the Nabiye expansion project at Cold Lake, environmental and efficiency projects at Syncrude, as well as exploration drilling and the advancement of the production pilot at Horn River. The Downstream segment’s capital expenditures were focused mainly on refinery projects to improve reliability, feedstock flexibility, energy efficiency and environmental performance.

The company’s cash balance was $920 million at September 30, 2011, up $653 million from $267 million at the end of 2010.

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Nine months highlights

Nine months 2011 vs. nine months 2010

Net income for the first nine months of 2011 was $2,366 million or $2.77 a share on a diluted basis, versus $1,411 million or $1.65 a share for the nine months of 2010.

For the nine months, increased earnings were primarily attributable to higher crude oil commodity prices of about $650 million, stronger industry refining margins of about $525 million, increased Cold Lake bitumen production of about $190 million and higher Syncrude volumes of about $70 million. These factors were partially offset by the unfavourable impact of the stronger Canadian dollar of about $205 million, higher royalty costs of about $190 million and lower conventional crude oil volumes of about $80 million due to third party pipeline reliability issues.

Upstream net income for the nine months of 2011 was $1,686 million, up $448 million from 2010. Earnings increased primarily due to the impacts of higher crude oil commodity prices of about $650 million, increased Cold Lake bitumen production of about $190 million and higher Syncrude volumes of about $70 million. These factors were partially offset by the unfavourable effects of higher royalty costs of about $190 million, the stronger Canadian dollar of about $150 million and lower conventional crude oil volumes of about $120 million, of which about $80 million was a result of the second and third quarter 2011 third-party pipeline issues.

The average price of Brent crude oil in U.S. dollars, a common benchmark for Atlantic Basin oil markets, was $111.96 a barrel in the nine months of 2011, up about 45 percent from the corresponding period last year. Increase in the average price of West Texas Intermediate (WTI) crude oil, a common benchmark for mid-continent North American oil markets, was limited to 23 percent due to the continued weakness in WTI crude oil markets. Increases in the company’s average realizations on sales of Canadian conventional crude oil and synthetic crude oil were in line with that of WTI. Increase in the company’s average bitumen realizations in Canadian dollars in the first nine months of 2011 was five percent to $60.90 a barrel as the price spread between light crude oil and Cold Lake bitumen widened.

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Nine months 2011 vs. nine months 2010 (continued)

Gross production of Cold Lake bitumen for the nine months was 159 thousand barrels a day this year, compared with 143 thousand barrels in the same period of 2010. Increased volumes were due to contributions from new wells steamed in 2010 and 2011, increased recovery and the cyclic nature of production at Cold Lake.

During the first nine months of the year, the company’s share of gross production from Syncrude averaged 75 thousand barrels a day, up from 71 thousand barrels in 2010. Increased production was due to improved operating reliability.

In the first nine months of the year, gross production of conventional crude oil was 17 thousand barrels a day, compared with 23 thousand barrels in 2010. Lower volumes were primarily due to third-party pipeline downtime, which reduced production at the Norman Wells field along with natural reservoir decline.

Gross production of natural gas during the nine months of 2011 was 259 million cubic feet a day, down from 282 million cubic feet in the nine months of 2010. The lower production volume was primarily a result of natural reservoir decline.

Nine months Downstream net income was $612 million, an increase of $436 million over 2010. Higher earnings were primarily due to favourable impacts of stronger industry refining margins of about $525 million and $40 million associated with improved refinery operations. These factors were partially offset by the unfavourable impacts of the stronger Canadian dollar of about $55 million and higher expenses of about $40 million mainly due to higher maintenance activities. Earnings in 2010 included a gain of about $25 million from sale of non-operating assets.

Chemical net income in the first nine months of 2011 was $111 million, up $67 million from 2010. Earnings were positively impacted by improved industry margins across all product channels, lower costs due to lower planned maintenance activities and higher polyethylene sales volumes.

For the nine months of 2011, net income effects from Corporate and other were negative $43 million, in line with the negative $47 million reported last year.

Key financial and operating data follow.

Forward-Looking Statements

Statements in this report relating to future plans, projections, events or conditions are forward-looking statements. Actual future results, including project plans, costs, timing and capacities; financing sources; the resolution of contingencies and uncertain tax positions; the effect of changes in prices and other market conditions; and environmental and capital expenditures could differ materially depending on a number of factors, such as the outcome of commercial negotiations; changes in the supply of and demand for crude oil, natural gas, and petroleum and petrochemical products; political or regulatory events; and other factors discussed in Item 1A of the company’s 2010 Form 10K.

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Attachment I

IMPERIAL OIL LIMITED

THIRD QUARTER 2011

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Attachment II

IMPERIAL OIL LIMITED

THIRD QUARTER 2011

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Attachment III

IMPERIAL OIL LIMITED

THIRD QUARTER 2011

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Attachment IV

IMPERIAL OIL LIMITED

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Attachment V

IMPERIAL OIL LIMITED

THIRD QUARTER 2011

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