J.K. Lasser's Your Income Tax 2013: For Preparing Your 2012 Tax Return

20.27 Record-Keeping Requirements

Your testimony—even if accepted by an IRS agent or a judge as truthful—is not sufficient to support a deduction of travel and entertainment expenses. By law, your personal claim must be supported by other evidence such as records or witnesses. The most direct and acceptable way is to have records that meet IRS rules discussed below. Failure to have adequate records will generally result in an examination of your return and in a disallowance of your travel and entertainment expense deductions. Only in unusual circumstances will evidence other than records provide all of the required details of proof. If your expenses are reimbursed by your company, you must keep records to support the reimbursement arrangement with your company (20.31).