Background: The role that lymph node dissection (LND) plays in the management of ovarian carcinosarcoma (OCS) is unclear due to its rarity. This study investigated lymph node metastasis (LNM) prevalence in women with early OCS and effects of LND and LNM on survival. Methods: Data of women diagnosed with OCS, whose primary tumor was confined to ovaries (American Joint Committee on Cancer [AJCC] T1) or pelvic cavity (AJCC T2), between 1988 and 2010 were collected from the Surveillance, Epidemiology, and End Results (SEER) database. Patients were classified into lymphadenectomy (LND [+]) and no lymphadenectomy (LND [-]) groups. Results: A total of 363 women were included. The prevalence of LNM was 9.6% in AJCC T1 and 16.3% in AJCC T2. Multivariate analysis showed that LND and AJCC T categories were independent prognostic variables, irrespective of cancer-specific survival (CSS) or overall survival (OS). Subgroup analysis by AJCC T categories revealed that LND (+) group in AJCC T2 had a better survival outcome compared to LND (-) group (CSS, HR [95% CI] = 0.61 [0.43-0.87]; OS, HR [95% CI] = 0.59 [0.42-0.83]). There was no survival difference between groups in AJCC T1 (CSS, HR [95% CI] = 0.96 [0.56-1.65]; OS, HR [95% CI] = 0.88 [0.56-1.38]). Multivariate analysis was further carried out in LND (+) group and demonstrated that LNM and AJCC T2 had poor CSS and OS. Subgroup analysis by AJCC T categories showed that worse survival was observed in LNM (+) group compared to LNM (-) group in AJCC T2 (CSS, HR [95% CI] = 3.62 [1.50-8.73]; OS, HR [95% CI] = 3.71 [1.59-8.68]) but not in AJCC T1 (CSS, HR [95% CI] = 1.78 [0.50-6.37]; OS, HR [95% CI] = 1.97 [0.61-6.39]). Conclusion: Regional lymphadenectomy should be performed in patients with AJCC T2 OCS. LND and LNM were not significantly associated with prognosis in AJCC T1 while LNM had a trend toward worse survival.