Objective: The aim of the present study was to examine the effects of incomplete surgery and adjuvant chemotherapy on the prognosis of patients with intraoperative rupture of capsulated stage I epithelial ovarian cancer (OvCa). Methods: A regional retrospective study was conducted between 1986 and 2019. Among 4,730 patients with malignant ovarian tumors, 534 women with International Federation of Gynecology and Obstetrics stage IA and IC1 epithelial OvCa were eligible. Differences in survival outcomes were examined between patients with stage IA and IC1 tumors and the effects of uterine preservation, complete-staging lymphadenectomy, and adjuvant chemotherapy were investigated by an in-depth subgroup analysis. To analyze therapeutic effects, baseline imbalances were adjusted using propensity score (PS). Results: The prognosis of patients with stage IC1 tumors was worse than those with stage IA. Surgical spill did not affect the site of recurrence. In the PS-adjusted subgroup analysis, uterine preservation (hazard ratio [HR]=1.669; 95% confidence interval [CI]=1.052–2.744), incomplete-staging lymphadenectomy (HR=1.689; 95% CI=1.211–2.355), and the omission of adjuvant chemotherapy (HR=3.729; 95% CI=2.090–6.653) significantly increased the HR of recurrence for patients with stage IC1 tumors compared to those with stage IA tumors. Adjuvant chemotherapy decreased the impact of rupture with uterine preservation (HR=0.159; 95% CI=0.230–1.168) or incomplete-staging lymphadenectomy (HR=0.987; 95% CI=0.638–1.527). Conclusion The present results suggest intraoperative rupture of capsulated stage I epithelial OvCa is associated with a poor prognosis. When chemotherapy is given for patients receiving incomplete surgery, there is no longer an increased risk of recurrence observed with the rupture.