Objective. To study the efficiency and safety of using tractocile (atosiban) in the treatment of pregnant women with threatened preterm labor to optimize therapy aimed at prolonging pregnancy. Subjects and methods. Nineteen women with threatened preterm labor at 25-34 weeks' gestation were examined. The drug was intravenously injected, as indicated, in 3 steps: bolus dose (6.75 mg), then infusion concentrate (300 µg/min) for 3 hours and that (100 µg/min) for as long as 45 hours. Results. Pregnancy ended in full-term baby birth in 17 (89.5%) of the 19 women. The babies were satisfactorily born. The therapy was ineffective in one pregnant woman. Despite being treated, her labor activity progressed and preterm birth occurred at 33 weeks' gestation. The baby was alive. In another patient, the therapy was inadequate: two cycles of atosiban therapy performed at 25-26 weeks and 26-27 weeks could prolong her pregnancy by 2 weeks. During this period, the fetal weight increased by 210 g (from 670 to 890 g); prophylaxis of fetal distress syndrome was made. The baby was alive. Adverse reactions caused by atosiban therapy were found in none of the patients. Conclusion. The investigation demonstrated the high efficacy of tractocile (atosiban) in treating threatened preterm labor.