All the anaesthetic machines in one District General Hospital were tested for faults on three occasions for both audit and re-audit using an extended checklist based on that devised by the Association of Anaesthetists of Great Britain and Ireland. Ninety completed checklists were analysed for the audit and 24 tests revealed 236 individual faults (range 1.1–64%). Sixty-five (27.5%) could have occurred on a day-to-day basis and 171 (72.5%) of the faults were non-recurring. Following introduction of COVERS (a pre-use checklist) re-audit of 102 completed checklists showed 20 tests revealing faults on 59 occasions (range 1.0–11.6%), 16 (27%) day to day and 43 (73%) non-recurring. COVERS supported by scheduled regular comprehensive checking delegated to another time and performer is recommended as the mandatory pre-use checklist.