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 <10 mIU/mL with single dose methotrexate treatment. Multiple dose methotrexate treatment and surgical treatment were considered as treatment failure. Results: 32 patients (64%) treated with single dose methotrexate, 14 patients (28%) treated with multiple dose methotrexate, and 4 patients (8%) treated with surgery. In the group with β-HCG level decrease > 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.