On the W-2 your employer reports the amount that has not been taxed (pre-tax). I know the description says employer contributions, it is really just the amount that has not been taxed. Since these amounts have not been taxed you do not get another tax break on your tax return for those payments. If you made a HSA contribution with taxed money (not through payroll) you would be able to get a deduction on your taxes for that amount.
