Objective: To evaluate the predictive ability of serum beta human chorionic gonadotropin (βhCG) levels and inflammatory markers derived from hemogram parameters in the success of methotrexate (MTX) treatment for tubal ectopic pregnancy. Methods: This retrospective study involved the examination of patients diagnosed with tubal ectopic pregnancy and treated with a single dose of MTX at our clinic between 2018 and 2023. The monocyte-to-lymphocyte ratio (MLR), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and systemic immune-inflammation index (SII) were calculated from blood samples taken at the time of presentation. βhCG levels were recorded on days 1, 4, and 7 of treatment. The patients were categorized into successful and unsuccessful treatment groups based on their response to MTX. Results: No statistically significant differences were found between the two groups regarding MLR, NLR, PLR, or SII values (P = 0.284, P = 0.097, P = 0.455, and P = 0.061, respectively). In the receiver operating characteristic analysis of serum βhCG from day 1 to day 4, the area under the curve value was calculated as 0.832. The cutoff value for the serum βhCG change from days 1 to 4 was −0.093 (−9.3%), with a sensitivity of 85.53% and specificity of 74.14%, and a positive predictive value (PPV) of 87.5%. Conclusion: There were no significant differences in inflammatory markers (MLR, NLR, PLR, and SII) between the successful and unsuccessful MTX treatment groups. The change in serum βhCG levels between days 1 and 4 can be used as an early predictor of MTX treatment success in tubal ectopic pregnancy.