An audit is an investigation conducted by the Internal Revenue Service (IRS) into a taxpayer's financial records and tax return(s). A field audit is a systematic investigation by the IRS that is conducted at the taxpayer's place of business or at the office of the individual who prepared the return.

A field audit is a comprehensive review of the entire set of financial records. It differs from a correspondence audit in that it is conducted in person rather than by mail. In addition, a field audit is typically scheduled for more complicated audits and is more serious.