This study investigated the effect of time of analgesia administration in 64 patients undergoing total abdominal hysterectomy. Patients received standard general anaesthesia and were divided randomly into two equal groups. At the time of fascia closure, patients in the intra-operative (Iop) group received 0.5 mg/kg pethidine intravenously. On arrival in the post-anaesthesia care unit, the same dose of pethidine was given to patients in the post-operative (Pop) group. All patients then used a patient-controlled analgesia pump to administer pethidine analgesia as required. Times to extubation, response to verbal stimulation and orientation, post-operative pain scores and analgesic consumption were recorded. Times to extubation and response to verbal stimulation were significantly longer in the Iop group. Pain scores, analgesic consumption and additional analgesic requirements were significantly higher in the Pop group in the first 2 h post-operatively. In conclusion, intra-operative administration of pethidine provided better pain management than post-operative administration.