Most organizations will know. IRS Publication 78, Cumulative List of Organizations , lists most qualified organizations. You can also search for qualified organizations online . Once you know the organization is qualified, make sure you claim the deduction in the correct manner. The approach here depends on your accounting method.
Corporations using the cash method of accounting can deduct contributions only in the tax year paid.
Accrual method offers more options When a corporation uses the accrual method of accounting, it faces additional options for when it can deduct these contributions. First, report the contribution on the corporation's return for the tax year. Include a copy of the resolution authorizing the contribution and a declaration stating the board of directors adopted the resolution during the tax year. Finally, make sure an officer authorized to sign the return signs the declaration. It could be a matter of differences in taxable income from one year to the next.