BACKGROUND: Although epidural block has been widely used to control post operative pain, still there are many problems to be solved such as inadequate pain control and difficulty in its techniques. Subarachnoid morphine and clonidine injection also has been used to control postoperative pain and as adjuvant to spinal anesthesia. We compared subarachnoid morphine or morphine and clonidine injection with epidural morphine and bupivacaine injection for postoperative pain control. METHOD: The effect of the different types of postoperative pain control method in low abdominal surgery were investigated. 30 patients were randomly divided into one of three groups; single intrathecal morphine injection (group M), single intrathecal morphine and clonidine injection (group M/C) and continuous epidural morphine and bupivacaine injection (group M/B) prior to induction of general anesthesia. Visual analogue scale (VAS), Prince-Henry Hospital score (PHS), patient satisfaction score and the side effects were investigated at emergence, 1, 2, 4, 8, 12, 24 and 48 hours after emergence of anesthesia. The blood pressure and heart rate were monitored 0, 5, 10 and 30 min, 1, 2, 24 and 48 hours after block for monitor the hemodynamic changes. RESULT: In group M/C, the VAS showed statistically significant decrease till first 24 hours after block and in group M/B after then (p<0.05). PHS and patient satisfaction scores were similar in all groups. The side effects, pruritis and nausea, by the opioids were more frequent in subarachnoid groups versus epidural group but that were tolerable without medication in most cases. In spite that systolic and diastolic blood pressures and heart rate were significantly low (p<0.05) in group M/C, there were no severe hypotension or bradycardia that need treatment. CONCLUSION: From these results, it seems that intrathecal morphine and clonidine combination therapy can be used as an another choice for postoperative pain control in low abdominal surgery.