In a prospective, randomized, double-blind study, we compared intravenous tenoxicam with rectal diclofenac for post-operative pain relief after day case arthroscopy or laparoscopic sterilization. Intravenous tenoxicam (40 mg) was administered as a single bolus at induction, or rectal diclofenac (100 mg) was administered immediately after induction. Both groups were similar with respect to age, weight, sex of the patients, the operation performed and the operative time. There were no significant differences observed between the groups for pain scores at 30 min, 60 min and 24 h post-operatively. The time to first analgesic requirement, the dose of pethidine administered and total analgesic requirements in the first 24 h post-operatively were equivalent in both groups. In view of the similar efficacy of both of these drugs, patient preference and ease of administration, the use of tenoxicam is appropriate in many patients undergoing day case surgery.