If you claim a deduction on your return of over $500 for all contributed property, you must attach a Form 8283 (PDF), Noncash Charitable Contributions, to your return. If you claim a total deduction of $5,000 or less for all contributed property, you need only complete Section A of Form 8283 (PDF). If you claim a deduction of more than $5,000 for an item or a group of similar items, you generally need to complete Section B of Form 8283 (PDF) which requires, in most cases, an appraisal by a qualified appraiser.

You will need to obtain and keep evidence of your car donation and be able to substantiate the fair market value of the car. If you are claiming a deduction of $250 or more for the car donation, you will also need a contemporaneous written acknowledgement from the charity that includes a description of the car and a statement of whether the charity provided any goods or services in return for the car and, if so, a description and estimate of the fair market value of the goods or services.

For more information on these requirements, refer to Publication 526, Charitable Contributions, Publication 561, Determining the Value of Donated Property; Form 8283, Noncash Charitable Contributions; and its instructions, and Tax Topic 506, Contributions.