My company has a mandated per diem pay. I don't want it. Can I claim the income on my taxes? Can I still deduct my expenses if what they pay is less than what the government allows.

Yes, you CAN claim the per diem pay as income (even if it is NOT taxable) on Line #21 of Form 1040 (Other income). You can and should also claim the expenses for which the per diem is being paid on Form 2106, though the expenses as an employee is deductible only as an itemized deduction.

Understand that if you have valid expenses for which the per diem is being claimed, it is likely that the per diem is NOT taxable income, but merely reimbursement for those expenses.