OBJECTIVE: Postterm choriocarcinoma is rare and seldom reported. Patients with postterm choriocarcinoma have unfavorable outcomes. Thus, we conducted a retrospective study to better understand this disease. METHODS: Thirty-five patients with postterm choriocarcinoma who received treatment at West China Second University Hospital from January 2011 to August 2022 were enrolled. RESULTS: The most common symptom in our cohort was abnormal uterine bleeding (25/35, 71.4%). Interval to diagnosis, serum β-hCG, and FIGO score or FIGO stage were not related to recurrence (P = 0.523, P = 0.812, P = 0.343, P = 0.440). However, the number of chemotherapy courses before achieving normal β-hCG (crude hazard ratio [HR] [95% confidence interval [CI]: 1.15 [1.04-1.26], P = 0.007) was positively related to recurrence, while the number of consolidation chemotherapy courses was negatively related to recurrence (crude HR [95% CI]: 0.51 [0.30-0.88], P = 0.015). Patients who received EMA-CO had a lower risk of recurrence, but the difference was not statistically significant (crude HR [95% CI]: 0.41 [0.08-2.06], P = 0.281). Patients who received other regimens (other than EMA-CO or 5-FU + Act-D) had a significantly higher risk of recurrence (crude HR [95% CI]: 8.30 [1.61-42.78], P = 0.011). CONCLUSIONS: The complete remission rate of postterm choriocarcinoma was 88.6% in our study. Serum β-hCG surveillance and/or pathological examination of curettage might lead to an earlier diagnosis. The number of consolidation chemotherapy courses was negatively related to recurrence. CLINICAL TRIAL NUMBER: Not applicable.