Context: It is known that clear cell carcinoma (CCC) and endometrioid carcinoma (EC) of the ovary is arising in endometiosis. But, in some cases, CCC and EC is not accompanied to endometriosis. Objective: The aim of this investigation was to compare outcomes of patients with CCC and EC of the ovary arising in endometriosis (ES) to CCC and EC not arising in ES. Methods:Clinicopathologic variables, progression-free survival (PFS) and overall survival (OS) were recorded. Student's t test and chi square test were used to analyze continuous and categorical data. The Kaplan–Meier method was used for survival analysis. Patients:This study retrospectively enrolled 224 CCC and EC patients treated in Samsung Medical Center from 2001 to 2015 to identify cancer arising in endometriosis. Main Outcome Measures: Comparing progression free survival(PFS) and Overall Survival (OS) of CCC and EC between arising in endometriosis (ES) and not arising in ES. Results: Forty-five cases arising in ES were identified and then compared with 179 cases without ES. CCC and EC arising in ES tended to be presented with early age (mean 45.2 years vs. 49.2 years p=0.003), early stage (stage I and II, 92.7% vs. 62.3 %, p<0.001), lower CA125 level (mean 307.1 vs. 556.7, p=0.041), higher percentages of no gross residual disease after surgery (87.8% vs.56.8%, p=0.001), and higher percentages of negative lymph node metastasis (82.9% vs. 59.0%, p=0.008) compared with those without ES. Kaplan-Meier curves for PFS and OS seemed to show better outcome for group arising in ES (p=0.014 for PFS, and p=0.010 for OS). However, association with ES was not significant in multivariate analysis Conclusions: CCC and EC with tumors associated with endometriosis appear to be diagnosed at an earlier stage and confers trend of better survival outcome.