A rule that sets aside certain types of income as nontaxable. There are many types of income that qualify under this rule, such as life insurance death benefit proceeds, child support, welfare and municipal bond income. Income that is excluded is not reported anywhere on Form 1040.

Generally, there is no limit to the amount of this type of income that can be received. One exception is municipal bond interest, which may be counted back as an alternative minimum tax preference item. Income that is excluded from taxation is generally accorded this status as a measure of relief for the recipient (or else as the result of powerful lobbying, as is the case with life insurance.)