OBJECTIVE To identify risk factors for readmission following methotrexate treatment for tubal pregnancy. METHODS A retrospective study undertaken in two tertiary medical centers, including all individuals with medically treated tubal pregnancy (N = 511), between December 2009 and June 2021. Individuals with and without readmission following methotrexate treatment were compared. The primary outcome was the readmission rate. Secondary outcomes included the rate of post-discharge gynecological emergency department visits, tubal rupture rate, and the eventual need for surgical treatment. RESULTS Readmission following methotrexate treatment occurred in 224/511 patients (43.8%). Most readmissions were due to abdominal pain or suspicion of treatment failure. Readmitted individuals were more likely to have a history of pelvic inflammatory disease and pretreatment serum human chorionic gonadotropin (hCG) >2000 mIU/mL. Both factors remained significantly associated with higher readmission rates in a logistic regression analysis (adjusted odds ratio [OR] 6.28, 95% confidence interval [CI] 1.30-30.45, and adjusted OR 2.73, 95% CI 1.83-4.07, respectively) after adjustment for age, endometriosis, tubal pathology, abdominal pain, and presence of yolk sac or embryo at diagnosis. A dose-dependent association was observed between pretreatment serum hCG levels and readmission rate (P < 0.001). Pretreatment hCG levels were also associated with tubal rupture and the eventual need for surgical treatment (P < 0.001 for both). A prediction model using hCG was not sufficiently accurate to predict readmission risk. CONCLUSIONS Readmission following methotrexate treatment for tubal pregnancy was independently associated with previous pelvic inflammatory disease and pretreatment serum hCG levels. The latter was also associated with surgical intervention rate.