Objective: To evaluate the efficacy of lymphadenectomy for early-stage primary mucinous ovarian cancer (MOC). Design: Retrospective observation study Setting: Surveillance, Epidemiology, and End Results (SEER) database for 2000-2018 Population or sample: The study population comprised 1848 patients with early-stage MOC Methods: MOCs were divided into two groups according to lymphadenectomy. Propensity score matching were performed to correct for deviations. Independent risk factors for overall survival (OS) were determined by multivariate analysis using Cox regression. The role of lymphadenectomy was performed in different populations by stratified analysis applying interaction analysis. OS was calculated by Kaplan-Meier curves and compared by log-rank test. Main outcome measures: Overall survival Results: In the study, almost 65.8% (n = 1214/1848) experienced lymphadenectomy. Lymphadenectomy (HR = 0.692, 95% CI = 0.516-0.927, P = 0.009), age at diagnosis (HR = 3.028, 95% CI = 1.477-6.208, P = 0.002), and laterality (HR = 2.013, 95% CI = 1.145-3.54, P = 0.015) were found to be associated with OS. The role of lymphadenectomy varied by age group and tumor laterality, and the 5-year survival rates of patients with bilateral tumors who had experienced lymphadenectomy with sampling and dissection, or for MOC over age 50 and were higher than that of patients who did not undergo lymphadenectomy. Conclusion: Lymphadenectomy with sampling and dissection has little impact on OS in patients with early MOC. Lymph node therapy can be discontinued in patients younger than 50 years, and lymph node sampling is recommended for patients older than 50 years or with bilateral tumors.