Income Tax Assessment Act 1997

Once you have the material required by section 900‑80 or 900‑85, you must retain it for 5 years. There is no need to lodge it with your *income tax return. The Commissioner may require you to produce it: see Subdivision 900‑G. The period for which you must retain it is called the retention period.

The 5 years start on the due day for lodging your *income tax return for the income year. If you lodge your return later, the 5 years start on the day you lodge it.

However, the *retention period is extended if, when the 5 years end, you are involved in a dispute with the Commissioner that relates to the expense. See section 900‑170.

If you do not retain the material for the *retention period, you cannot deduct the expense. If you have already deducted it, your assessment may be amended to disallow the deduction.

If you lose any of the material, there are rules that might help you in section 900‑205.