Objective The aim of this study was to evaluate the prognostic value of serum CA-125 in advanced epithelial ovarian cancer with complete remission after primary adjuvant chemotherapy. Methods We reviewed the records of 120 patients with advanced epithelial ovarian cancer who underwent primary surgery followed by adjuvant therapy at our institution between January 1998 and December 2005. Results The median progression free survival was 21.6 months and 12.5 months in patients with nadir CA-125 levels ≤10 U/mL and 10 to 35 U/mL, respectively. Median overall survival in the same respective order was 130.2 months and 35.3 months. The level of serum CA-125 after the first cycle of adjuvant chemotherapy was most significantly higher in the recurrent group compared with the non-recurrent group. The optimal cut point of CA-125 on the receiver operating characteristic curve was 35 U/mL. Median progression free survival was 64.6 months and 12.8 months in patients with nadir CA-125 levels ≤35 U/mL and >35 U/mL, respectively, after first cycle of adjuvant chemotherapy. Conclusion Serum CA-125 level after the first cycle of adjuvant chemotherapy is a strong independent prognostic factor for advanced epithelial ovarian cancer with complete response.