Are the expenses recorded in box 14? That is a memo field, it is not taxable, forget about it.
Are the expenses included in your box 1 wages? Then read below.
If the employer has an accountable plan (you prove expenses with receipts), then they should not include the reimbursement on your W-2. You should ask them for a corrected W-2. If they refuse, you have the option of submitting a "substitute W-2" form showing what you believe to be the accurate numbers, but this will almost certainly be questioned by the IRS. So you want to have proof that you asked your employer, they refused, and you will need proof that you employer has an accountable expense plan.
If the expense plan is not an accountable plan, then it correct to include the payment as taxable wages, and you are not allowed to make any adjustments or deductions from that amount.
