Rev. date: 08/04/2012
In general, an amount contributed to a 401(k) account cannot be used as an IRA deduction. However, if the 401(k) plan has a deemed IRA feature, contributions to the deemed IRA may be deductible in accordance with the IRA contribution
rules.
A pre-tax 401(k) contribution is already excluded from your federal (and most state and local) taxable income, as it is not included in box 1 taxable wages of your W-2 form. Deemed IRA contributions are included in box 1 and you use the normal IRA contributions rules to determine their
deductibility.