Filing an income tax return puts in motion the process of determining a taxpayer's tax liability for a particular year. Where no return is filed, the statute of limitations does not begin to run and this process does not commence.

The purpose of filing income tax returns is to put in motion the process of determining a taxpayer's tax liability for a particular year. Where no return is filed, this process does not commence. The significance of the failure to file a return is that the statute of limitations does not begin to run and there is no time limit on any proceedings by the Service against the taxpayer for failure to file a return.►

Note that a document submitted has to convey certain minimum information before it will be recognized as a "return"; for example, filing a Form 1040 without the critical elements of income, deductions, or taxable income, under the claim of protection under the Fifth Amendment, has been held not to constitute "filing a return" so as to start the running of the limitations period.►

The taxpayer is required to complete returns accurately and completely.►

The preparation of income tax returns raises questions such as whether certain items in a particular year are taxable income, whether items are properly deductible, the proper application of credits, the use of accounting periods, and the computation of tax liability; accordingly, a return may be required even though the result is that the filer has no taxable income.►

Returns filed in order to report withholding create special problems and are dealt with in other chapters.►