It depends, but probably is not reported on your W2. If your employer used a qualified accountable plan, any amounts you received for mileage is reimbursement and is not taxable. If they did not use an accountable plan, it would be income taxable to you and would be reported on Form W2. But, since these expenses are no longer deductible at the personal level, (but still are at the business level with an accountable plan), it is more likely than not that your reimbursement is non-taxable and non-reportable on your return, but check with your employer to be certain.