Yes, you are required to have a receipt. If you claim the donation without proper receipts, you are taking a risk if audited, but most people are not audited**.
If audited, the IRS will want to see several things, and a receipt is only the start:
- A receipt from the organization showing you donated the items
- Your own list of items, including when you obtained the items (approximately), how much you paid, and what condition they were in (good, fair or poor)
- How you determined the value you claimed (eBay prices, thrift store prices, something else)
Also know that some taxpayers have been denied a large non-cash donation even with a receipt from the charity, because the receipt was not specific enough. If the receipt is just a standard form and is not itemized, how could you prove that the donation actually contained all the items on your separate list? This may not happen often, but it can happen. You may want to write out your itemized list and have someone from the charity co-sign it or stamp it, in addition to getting their generic receipt.
**I actually got a letter about 15 years ago asking me to mail in proof of all my charity donations. Because I had amended that return, the first return no longer "counted" and they closed the case. For whatever reason, they did not ask for proof of the donations on the amended return. I'm glad they didn't, but it would have been interesting.
