Objectives: To evaluate the impact of the uterine artery Doppler values and the change of β-Human chorionic gonadotropin (β-HCG) levels from day 0 to day 4 for prediction of the success of single dose methotrexate treatment in tubal pregnancy cases. Study Design: 50 patients with tubal pregnancy were included the prospective study. The location and size of ectopic pregnancy, bilateral uterine artery pulsed color doppler imaging was examined by ultrasonography and serum β-HCG levels were measured on day 0, 4, 7 of treatment. Success was defined as decrease of β-HCG level 15.04% on day 4, single-dose methotrexate therapy were 3.82 times more successful than the group without > 15.04% β-HCG decrease. However, no significant alteration of uterine artery Doppler measurements was determined on the same days. Conclusion: Reduction rate in the β-HCG level on day 4 of treatment can be used in determination the success of single-dose methotrexate therapy.