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.