Objective Pulmonary edema is recognized as a severe side effect of ritodrine hydrochloride. Recently, the number of twin pregnancies has been increasing. Few studies have reported the association between total dose of ritodrine hydrochloride prior to delivery and pulmonary edema in twin pregnancy. We aimed to examine this association and determine the optimal cutoff threshold of total ritodrine hydrochloride dose to predict the incidence of pulmonary edema in twin pregnancy, based on obstetric records. Design Retrospective cohort study. Setting Yamanashi Prefectural Central Hospital, Japan Participants Two hundred twenty-six women with twin pregnancy who delivered at Yamanashi Prefectural Central Hospital between September 2009 and November 2016 Methods The obstetric records of the participants were analyzed. We defined one unit of ritodrine hydrochloride as 72 mg per 24 h continuous transfusion at 50 µg/min to calculate the dose of ritodrine used for tocolysis. Outcome measures Multivariable logistic regression analysis was performed to examine the association between total dose of ritodrine hydrochloride used for threatened preterm labor and pulmonary edema, while controlling for potential confounding factors. Then, a receiver-operating characteristic curve was used to determine the optimal cutoff of total ritodrine dose to predict pulmonary edema incidence. Results Mean maternal age was 32 (range, 18-46) years; 143 participants were nulliparous (63.3%), 109 had (48.2%) term deliveries, and 194 (85.8%) had cesarean deliveries. The overall incidence of pulmonary edema was 13.7% (31/226). Multivariable analysis showed that the total dose of ritodrine was significantly associated with pulmonary edema (adjusted odds ratio 1.02; 95% confidence interval, 1.004-1.03). The best cut-off point to predict the incidence of pulmonary edema was 26 units (1872 mg) (sensitivity, 61.3%; specificity, 87.8%). Conclusion Our results suggest that consideration of the total dose of ritodrine hydrochloride is helpful in the management of patients with threatened preterm labor in twin pregnancy.