Exhibit 99.3

OSI SYSTEMS, INC. AND SUBSIDIARIES

UNAUDITED PRO FORMA CONDENSED COMBINED FINANCIAL INFORMATION

The following unaudited pro forma condensed combined financial information and related notes present the historical condensed combined financial information of OSI Systems, Inc. (collectively, with its consolidated subsidiaries, “OSI Systems” or the “Company”) and American Science and Engineering, Inc. (“AS&E”) after giving effect to OSI Systems’ acquisition of AS&E that was completed on September 9, 2016. AS&E is a leading provider of detection solutions for advanced cargo, parcel, and personnel inspection. The unaudited pro forma condensed combined financial information gives effect to the acquisition of AS&E based on the assumptions, reclassifications and adjustments described in the notes to the unaudited pro forma condensed combined financial information.

The unaudited pro forma condensed combined balance sheet as of June 30, 2016 has been presented as if the acquisition of AS&E had occurred on such date.  The unaudited pro forma condensed combined statement of operations for the year ended June 30, 2016 has been prepared as if the acquisition of AS&E had occurred on July 1, 2015. The historical financial information is adjusted in the unaudited pro forma condensed combined financial information to give effect to pro forma adjustments that are (1) directly attributable to the AS&E acquisition, (2) factually supportable and (3) with respect to the statement of operations, expected to have a continuing impact on the combined results. The unaudited pro forma financial information does not reflect the cost of any integration activities or the benefit that may result from the merger of OSI Systems and AS&E. The unaudited pro forma condensed combined financial information is not necessarily indicative of, or intended to represent, the results that would have been achieved had the transaction been consummated as of the dates presented or of the results that may be achieved in the future.

The unaudited pro forma condensed consolidated combined financial information has been prepared pursuant to Regulation S-X Article 11. Accordingly, the assets acquired and liabilities assumed have been recorded at their estimated fair values at the date of acquisition. Any excess of the estimated purchase price of $266 million over the estimated fair value of the net assets acquired has been recorded as goodwill. The preliminary estimates of fair values are reflected in the accompanying unaudited pro forma consolidated combined financial information.

The unaudited pro forma condensed combined financial information should be read in conjunction with the historical consolidated financial statements and accompanying notes of OSI Systems included in the Annual Report on Form 10-K for the fiscal year ended June 30, 2016, and the audited financial statements of AS&E for the fiscal year ended March 31, 2016 and the unaudited financial statements of AS&E for the three months ended June 30, 2016, included as Exhibits 99.1 and 99.2 to this Form 8-K/A.

OSI SYSTEMS, INC. AND SUBSIDIARIES

UNAUDITED PRO FORMA CONDENSED COMBINED BALANCE SHEET

AS OF JUNE 30, 2016

(amounts in thousands)

See accompanying notes to unaudited pro forma condensed combined financial information.

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OSI SYSTEMS, INC. AND SUBSIDIARIES

UNAUDITED PRO FORMA CONDENSED COMBINED STATEMENT OF OPERATIONS

(amounts in thousands, except per share data)

See accompanying notes to unaudited pro forma condensed combined financial information.

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OSI SYSTEMS, INC. AND SUBSIDIARIES

NOTES TO UNAUDITED PRO FORMA CONDENSED COMBINED FINANCIAL INFORMATION

1. Basis of Pro Forma Presentation

On September 9, 2016, the Company acquired by merger 100 percent ownership interest of American Science and Engineering, Inc. (“AS&E”), a leading provider of detection solutions for advanced cargo, parcel, and personnel inspection.  OSI Systems paid $37 per share in cash for total cash consideration of $264.6 million.  The Company financed the acquisition by a combination of cash on hand and borrowing under its existing revolving bank line of credit. In addition, the Company issued restricted stock units (“RSUs”) for the Company’s common stock as a replacement award for RSUs originally granted by AS&E. Further, the Company has preliminarily estimated that $1.4 million of the fair value of the replacement award pertained to the precombination service period. Thus, this amount has been considered as part of the purchase price consideration for a total estimated purchase price of $266 million.  The impact of the replacement RSUs on the pro forma diluted number of shares was de minimis.

The unaudited pro forma condensed combined balance sheet as of June 30, 2016 and the unaudited pro forma condensed combined statement of operations for the year ended June 30, 2016 are based on the historical financial statements of OSI Systems and AS&E after giving effect to OSI Systems’ acquisition of AS&E, which was completed on September 9, 2016, and the assumptions, reclassifications and adjustments described in the notes herein.

The unaudited pro forma condensed combined financial information is not intended to represent or be indicative of the results of operations or financial position of OSI Systems that would have been reported had the acquisition been completed as of the dates presented, or of future results of operations or financial position. The unaudited pro forma condensed combined financial information does not reflect the cost of any integration activities or the benefit that may result from the realization of future cost savings from operating synergies, or from the realization of any revenue, tax, or other synergies that may arise due to the integration of OSI Systems and AS&E.  The unaudited pro forma condensed combined financial information should be read in conjunction with OSI Systems’ Annual Report on Form 10-K for the year ended June 30, 2016, as filed with the Securities and Exchange Commission on August 19, 2016, and in conjunction with the financial statements of AS&E, presented as Exhibits 99.1 and 99.2 of this Form 8-K/A.

The acquisition of AS&E has been accounted for under the acquisition method of accounting in accordance with Accounting Standards Codification 805, Business Combinations (“ASC 805”) under which the total estimated purchase price consideration is allocated to the tangible and intangible assets acquired and liabilities assumed based on their fair value as of the acquisition date with the excess amount of the purchase price over the fair value of the net assets acquired and liabilities assumed recorded as goodwill. OSI Systems’ preliminary valuation of the fair values of net assets acquired, including intangible assets, and liabilities assumed is based on preliminary estimates and assumptions and is subject to change pending finalization of the valuations. These preliminary estimates and assumptions are subject to change during the measurement period (up to one year from the acquisition date) as OSI Systems finalizes the valuations of the tangible and intangible assets acquired and liabilities assumed from the acquisition. Any changes to the preliminary estimates of the fair value of the assets acquired and liabilities assumed will be recorded as adjustment to those assets and liabilities with the offset being recorded to goodwill.

The unaudited pro forma condensed combined balance sheet as of June 30, 2016 is presented as if the acquisition occurred on June 30, 2016.  The unaudited pro forma condensed combined statement of operations for the year ended June 30, 2016 is presented as if the acquisition occurred on July 1, 2015. Due to different fiscal period ends, which are not in excess of 93 days apart, the pro forma condensed combined statement of operations for the year ended June 30, 2016 combines the historical results of OSI Systems for the year ended June 30, 2016 and the results of AS&E for the year ended March 31, 2016.

Based upon OSI Systems’ review of AS&E’s significant accounting policies, the pro forma financial information assumes there will be no adjustments required to conform AS&E’s accounting policies to OSI Systems’ accounting policies. However, certain balances from the historical financial statements of AS&E were reclassified to conform to OSI Systems’ financial statement presentation as further discussed in Notes 3 and 4 to the unaudited pro forma condensed combined financial information. As of the date of this report, OSI Systems is not aware of any other differences that would have a material impact on the unaudited pro forma condensed combined financial information.

2. Acquisition Accounting Adjustments

The acquisition of AS&E has been accounted for under the acquisition method of accounting in accordance with ASC 805. Under the acquisition method of accounting, the assets acquired and liabilities assumed have been recorded at their estimated fair values at the date of acquisition. Any excess of the total estimated purchase price of $266 million over the estimated fair value of the net assets acquired has been recorded as goodwill.   OSI Systems’ preliminary valuation of the fair values of net assets acquired, including

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intangible assets, and liabilities assumed is based on preliminary estimates and assumptions and is subject to change pending finalization of the valuations. Any changes to the preliminary estimates of the fair value of the assets acquired and liabilities assumed will be recorded as adjustment to those assets and liabilities with the offset being recorded to goodwill.

The following is a preliminary estimate of the assets acquired and the liabilities assumed by OSI Systems in the acquisition, reconciled to total estimated purchase consideration (in thousands):

3. Pro Forma Adjustments — Balance Sheet (in thousands)

A) Cash and cash equivalents:

Note 1 —     Immediately following the close of the acquisition, OSI Systems used a portion of AS&E’s existing cash on hand to pay down the revolving bank line of credit that was used to fund the transaction.

B) Accounts receivable — Reclassification of AS&E’s Unbilled costs and fees.

C) Goodwill — To record the estimated fair value of the goodwill had the acquisition occurred on June 30, 2016.

D) Intangibles assets, net — To record the estimated fair value at the date of acquisition of the identifiable intangible assets acquired:

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E) Other assets:

F) Bank lines of credit:

G) Other accrued expenses and current liabilities:

H) Other long-term liabilities — Reclassification of AS&E’s Deferred revenue — long term.

I) Stockholders’ Equity — Elimination of AS&E’s historical equity balances had the acquisition occurred on June 30, 2016 and the issuance by the Company of replacement restricted stock unit awards related to the acquisition.

4. Pro Forma Adjustments — Statement of Operations (in thousands)

J) Net revenues — Products:

K) Net revenues — Services — Reclassification of sales of parts to support field services from Net revenues — Products.

L) Cost of goods sold — Products:

M) Cost of goods sold — Services:

N) Selling, general and administrative:

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O) Research and development:

P) Impairment, restructuring and other charges:

Q) Interest and other expense, net:

Note 1 —     Pursuant to the terms of the Company’s credit facility, the pro forma annual interest was calculated using the one-month LIBOR plus the applicable margin on the $196 million of net borrowing less the reduced commitment fees. In conjunction with the acquisition, the Company issued $16 million of letters of credit under the Company’s credit facility as guarantees for outstanding AS&E guarantees.  The additional interest less commitments fees for the letters of credit issued were also included in the pro forma interest above. In the event that the Company had not used $69 million of AS&E cash to pay down the revolving bank line of credit immediately following the acquisition, the pro forma interest expense would be increased by approximately $1.4 million. If the actual interest rate differed from the interest used for the pro forma interest expense above by 1/8%, interest expense would increase or decrease by $0.2 million.

R) Provision (benefit) for income taxes — To record the tax effect of pro forma adjustments at an estimated blended tax rate of 39%.

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