Can I deduct employer 401k contributions on my taxes or does contributions have to come out of my paycheck?

[jlizam23]

I have a fully vested 401k plan. Under my union contract, I receive a small blended benefit amount separate from my salary not listed on my paycheck that goes into my medical insurance reserve that caps at 3 months of my health and dental insurance premiums. Once my medical reserve reaches it's cap, my blended benefit amount goes into my 401k listed as excess health and welfare contributions.

[DoninGA]

Employer contributions are not deductible on a tax return.

[jlizam23]

So the contributions have to come out of my check in order to be able to deduct?

[Opus 17]

By law and design, contributions can only be made to a 401k via your employer.  This applies to both free money contributed by your employer as a a benefit, and any voluntary contributions you make by salary reduction.  Both types of contributions are considered identical under the tax law.  They should not be included in your W-2 box 1 taxable wages — that is your tax deduction.  They are not included in taxable income so you never pay income tax.  You can't list them as a separate tax deduction because they are already not taxed.