The utility of cancer antigen 125 (CA-125) levels as an adjunct method of monitoring patients with uterine papillary serous carcinoma (UPSC) or endometrial serous carcinoma after surgery and adjuvant treatment has been reported. Our goal was to determine the significance of rising CA-125 levels within the normal range in these patients in the posttreatment surveillance setting. All patients with UPSC who underwent surgical staging and had preoperative CA-125 measurement from 1999 to 2008 were included in this analysis. Information was extracted from records to assess the changes in CA-125 values with clinical and/or radiographic detection of recurrence. Of the 56 evaluable patients, 23 (41%) recurred. Of the 23 patients that recurred, 11 had serial CA-125 levels measured in remission. Elevated CA-125 levels at diagnosis were significantly associated with disease recurrence and advanced stage (P ¼ .01, P ¼ .001, respectively). The rise in CA-125 by 10 U/mL in the normal range and 15 U/mL were associated with disease recurrence (P < .001, P < .001, respectively). In multivariate analysis, only CA-125 level 15 U/mL was significantly associated with worse progression-free survival. In this small cohort of patients with recurrent UPSC after remission, surveillance of CA-125 levels may have a role in disease surveillance and management.