A Nondeductible Contribution is money you put into a traditional IRA that you can’t subtract from your taxable income for the year. This usually happens if you or your spouse have a retirement plan at work and your income is above certain limits. Even though you don’t get a tax break up front, the money still grows tax-deferred, meaning you don’t pay taxes on earnings until you withdraw them. You’ll need to track these contributions carefully so you don’t pay taxes on them again when you take the money out later.