Distributions from retirement plans must be included in income unless they represent an employee’s own contribution, such as after-tax employee contributions, or if the distribution is a qualified distribution from a Designated Roth Account. If the employee is under age 59 ½, see Tax on Early Distributions. If the employee was born before January 2, 1936, he or she may use a special tax rule.
Publication 575, Pension and Annuity Income
Publication 560, Retirement Plans for Small Business (SEP, SIMPLE, and Qualified Plans)
Publication 590-B, Distributions from Individual Retirement Arrangements (IRAs)
Publication 554, Tax Guide for Seniors