OBJECTIVES: To assess the efficacy and safety of atosiban in pregnant women under threat of preterm birth. METHODS: A systematic review was carried out, inclusion criteria were adult pregnant women diagnosed with preterm labor threat with the following characteristics: regular uterine contractions lasting at least 30 seconds, contraction frequency greater than 4 every 30 minutes, cervix dilatation from 1 to 3 cm, gestational age from 24 to 33 weeks and normal fetal heart rate (110 – 160 bpm). Atosiban was set as intervention and the comparators were nifedipin, indomethacin, terbutaline, fenoterol and placebo. Assessed outcomes were: Gestational age at birth, delay in the timing of birth, neonatal mortality, neonatal respiratory distress syndrome, intraventricular hemorrhage, periventricular leukomalacia, rate of maternal adverse events, rate of neonatal complications. Quality of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) tool. The comparison measurements found on studies were extracted in order to perform a network meta-analysis. Results were expressed through forest plots. RESULTS: