EXHIBIT 23

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We consent to the incorporation by reference in Registration Statement Nos. 333-88542, 333-125193, and 333-154917 on Form S-3, Registration Statement No. 333-129088 on Form S-4, and Registration Nos. 333-51316 (as amended by Post-Effective Amendment No. 1), 333-64076 (as amended by Post-Effective Amendment No. 1), 333-97871, 333-104855, 333-114682, and 333-122232 on Form S-8 of our reports dated October 27, 2009, relating to the consolidated financial statements of Monsanto Company and subsidiaries (which report expresses an unqualified opinion and includes an explanatory paragraph regarding the Company’s adoption of Statement of Financial Accounting Standards No. 157, Fair Value Measurements; Financial Accounting Standards Board Interpretation No. 48, Accounting for Uncertainty in Income Taxes — an interpretation of FASB Statement No. 109; and Statement of Financial Accounting Standards No. 158, Employers’ Accounting for Defined Benefit Pension and Other Postretirement Plans — an amendment of FASB Statements No. 87, 88, 106, and 132(R); effective September 1, 2008, September 1, 2007, and August 31, 2007, respectively), and the effectiveness of Monsanto Company’s internal control over financial reporting, appearing in this annual report on Form 10-K of Monsanto Company for the year ended August 31, 2009.

/s/ DELOITTE & TOUCHE LLP

St. Louis, Missouri
October 27, 2009