Form 1065 is the U.S. Partnership Return of Income. It is used to report the income, gains, losses, deductions, and credits from the operation of a partnership business. All partnerships must file Form 1065 annually, unless the partnership meets certain exceptions outlined in the instructions for Form 1065. The due date for filing Form 1065 is the 15th day of the 3rd month after the end of the partnership’s tax year. For example, if the partnership’s tax year ends on December 31, the due date for filing Form 1065 is March 15 of the following year.