Abstract: Objective: To assess the serum CA 125 regression in advanced ovarian carcinoma patients treated with paclitaxel/platinum (TP) and platinum/ epirubicin/ ifosafamide (PAC) during early chemotherapy and evaluate the relationship between survival and CA125 regression during first-line chemotherapy. Methods:This retrospective investigation assessed 122 and 95patients with stagesⅡc- Ⅳovarian carcinoma, respectively, who underwent initial surgery followed by TP or PAC chemotherapy. Only epithelial ovarian cancers were included. CA125 half-life was calculated by mono-compartmental logarithmic regression. The nadir CA 125 concentration of each patient was also studied. Additionally, t-test was used in comparing CA125 half-life and nadir CA125 between the two groups. Survival analyses for progression-free survival (PFS) and overall survival (OS) were performed by using univariate (Kaplan-Meier) and multivariate (Cox) models on the data. Results: There was no significant difference in CA125 half-life and nadir CA125 concentration between the two groups (P >0.05). CA125 half-life and nadir CA125 concentration had a univariate prognostic value for PFS and OS (P<0.0001) in all of the patients. However pre-chemotherapy CA125 and different chemotherapy agents were not prognostic factors for PFS and for OS ( P>0.05, for each). In Cox model, CA125 half-life (P=0.0006), residual tumor (P<0.0001), and nadir concentration ( P=0.0032) were significant prognostic factors for DFS. For OS, CA125 half-life ( P=0.0013), residual tumor (P<0.0001), and nadir concentration ( P=0.0118) were also the significant prognostic factors. Conclusion : There is no significant difference in serum CA125 regression between patients who are treated with PAC and PT during early chemotherapy. CA125 half-life and nadir CA 125 concentration are independent prognostic factors in advanced ovarian cancer.