Different IRAs have different tax treatments. Traditional IRAs, as well as SEPs, SIMPLEs, and 401(k)s are all taxed as income in retirement. Roth IRAs are not taxed.

Traditional IRAs and the other pretax accounts will have distributions that are also includable in the Modified Adjusted Gross Income calculations which may subject them to 3.8% Medicare surtax, as well as the income calculations which determine what portion of Social Security income may be taxable in retirement.

Many people do not realize that up to 85% of social security income may be subject to income taxes.