BACKGROUND: Atracurium, a nondepolarizing muscle relaxant, is eliminated by Hofmann elimination and not affected by pseudocholinesterase(pChe). Many reports show fall in pChe activity during pregnancy and our measurement failed to prove it. However, the authors found previously the infusion rate of mivacurium, which is metabolized by pChe, to achieve surgical relaxation is decreased. So, we compared the difference in the infusion rate of atracurium between full-term pregnant and nonpregnant women. METHODS: Muscle relaxation of full-term pregnant women(C group, n=10) and nonpregnant women (Non-C group, n=10) was maintained by continuous infusion of atracurium to keep 1st response of TOF at 5 1%. After discontinuance of infusion, recovery index was measured without reversals using the accelerograph. RESULTS: There was no significant difference in infusion rate of atracurium to maintain 1st twitch response of TOF at 5 1% and recovery index between two groups. There was little correlation between the total infusion time and infusion rate, or between the total infusion time and recovery index. CONCLUSION: The atracurium infusion rate in parturients to maintain muscle relaxation was not different from that in non-parturients. For Cesarean section, the usual infusion rate of atracurium is recommended to achieve the adequate surgical relaxation.