Hello and thank you for coming to Just Answer. We appreciate the opportunity to help you with your tax questions. I happen to be a tax preparer in the state of Idaho, so I can help you with your question. The general rule on whether vehicle registrations are deductible, is that any vehicle registration that is based on the value of the vehicle is deductible. In Idaho, most automobile registrations are based on a set fee, not the value of the vehicle, so the registration is not deductible. However, if you have an RV or other vehicle where the registration costs are based on the value of the vehicle, that registration is deductible. As an easy rule of thumb, if you have to tell the DMV what you paid for the vehicle (other than the very first registration if you have to pay sales tax on the vehicle), then you can deduct the cost of registering the vehicle.