A traditional IRA and a 401(k) are tax-deferred retirement accounts. The money is left in these types of accounts to grow and collect dividends. However, when you start taking withdrawals you will pay taxes. Roth IRAs differ in that contributions are not tax-deductible, but when you begin taking withdrawals this will be tax-free. A portion of your social security benefits may be taxed if your provisional income exceeds $25,000.