OBJECTIVE: In the present study we aimed to compare the effects of sitting and left lateral decubitis position on block levels and hemodynamic parameters in patients undergoing cesarean section under combined spinal-epidural anesthesia. MATERIALS AND METHODS: Thirty parturients were randomized into sitting (Group 1, n=15) and left lateral decubitis position groups (Group 2, n=15) and combined spinal-epidural anesthesia was performed using 8.5 mg plain bupivacaine. Systolic arterial pressure, heart rate, level of block, time to reach block level, amount of ephedrine used and APGAR scores of newborn were assessed. RESULTS: Systolic arteriel pressures were different between groups at 4., 6.,8. and 10. minutes (p< 0,05). Maximum decrease and maximum decrease time in systolic arteriel pressures were observed earlier in Group I. Hypotensive period was longer and consumption of ephedrine was more in Group I (p< 0,001). The number of patients in whom block level reached T4, sensoriel and motor block levels were significant in Group I. The time to reach block level of T4 was shorter in Group I.CONCLUSION: In cesarean section intrathecal 8.5 mg plain bupivacaine was adequate in sitting position but inadequate in left lateral decubitis positon. It could be appropriate in combined spinal-epidural anesthesia technique. Although the block levels were higher and onset time of block was shorter in sitting position with plain bupivacaine, long-lasting and profound hypotension may be detrimental for the mother and the fetus. Therefore, we concluded that it would be better to perform combined spinal-epidural anesthesia in left lateral decubitis position.