Objective: To assess whether success rate differs in single-dose versus multiple-dose administration of methotrexate(MTX)-in medical management of unruptured ectopic pregnancies. Design: Prospective randomized clinical trial. Setting: Tertiary university hospital. Patient(s): The study population included 108 patients presenting with unruptured ectopic pregnancies who fulfilled the criteria for medical management. Intervention(s): A single dose(study group) or multiple doses(control group) of MTX were administered IM. Main Outcome Measure(s): Success rate of medical management in each group. Result(s): Of the 54 patients on the single-dose protocol, treatment was considered successful in 48 patients(88.9%). Of the 54 patients on the multiple-dose protocol, 50 participants responded to the treatment(92.6%). The diffe- rence between success rates in the two groups was not statistically significant(P=.7; odds ratio 0.64; 95%confidence interval 0.17-2.4). In the single-dose and multiple-dose groups, 15(27.8%) and 20(37%) patients, respectively, had complications(P=.3). Conclusion(s): The results of our study showed that single-dose treatment with MTX could be as successful as multiple doses. The incidence of complications did not differ between the two groups. It appears that single-dose treatment could be the first line of treatment in selected patients. Objective: To assess whether success rate differs in single-dose versus multiple-dose administration of methotrexate (MTX) -in medical management of unruptured ectopic pregnancies. Design: Prospective randomized clinical trial. Setting: Tertiary university hospital. Patient (s): The Intervention (s): A single dose (study group) or multiple doses (control group) of MTX were administered IM. Main Outcome Measure (s): Of (s): Of the 54 patients on the single-dose protocol, treatment was considered successful in 48 patients (88.9%). Of the 54 patients on the multiple-dose protocol, 50 participants responded to the treatment (92.6%). The diffe-rence between success rates in the two groups was not statistically significant (P = .7; odds ratio 0.64; 95% confidence interval 0.17-2.4). In the single-dose and multiple -do The results of our study showed that single-dose treatment with MTX could be as successful as (18.8%) and 20 (37%) patients, respectively, had complications (P = .3) The incidence of complications did not differ between the two groups. It appears that single-dose treatment could be the first line of treatment in selected patients.