The number of cases performed in ambulatory surgical units is continuing to increase. This is due to economic pressures, patient expectation and improvement in surgical and anaesthetic techniques. Optimal preoperative preparation of outpatients makes ambulatory surgery both safer and more acceptable for patients and staff. Advances in day case anaesthesia include the use of anaesthetic agents of short duration and increasing use of regional anaesthetic techniques. The basic principles for day case procedures of good analgesia, adequate fluid administration and the avoidance of postoperative nausea and vomiting hold for diabetic patients. Control of postoperative nausea and vomiting is important in all day surgery patients as it strongly affects patient satisfaction and contributes to prolonged hospital stay. Such practices ensure prompt resumption of oral intake and return to normal anti-diabetic medication, which enables patients with diabetes mellitus to be treated successfully on an ambulatory basis.