Objective: The cyclase-associated actin cytoskeleton regulatory protein 2 (CAP2) is a protein that regulates actin dynamics to control cell cycles and cell migration. Evidence indicates that CAP2 overexpression contributes to cancer progression in several tumor types; however, the potential role of CAP2 expression in ovarian carcinogenesis remains unclear. This study aims to clarify the clinicopathological and prognostic significance of CAP2 expression in epithelial ovarian tumor. Methods: CAP2 expression was analyzed in seven ovarian cancer cell lines using quantitative PCR, western blotting, and immunocytochemistry. CAP2 immunohistochemistry was conducted in 432 consecutive ovarian carcinomas that were removed by complete or optimal resection, as well as in 55 borderline and 65 benign cystic lesions. CAP2 expression level was defined as low, intermediated, or high to correlate with clinicopathological factors. Results: CAP2 expression levels in ovarian cancer cell lines varied by differing carcinoma subtypes. Higher levels of CAP2 expression were associated with Type II histology, residual lesion, lymph node metastasis, ascites cytology, and higher clinical stage. High CAP2 expression level was observed in 26 (23%) of 111 Type II ovarian cancers and 16 (5%) of 321 Type I ovarian cancers, but not in any of borderline or benign lesions. CAP2 expression in epithelial ovarian cancer was an independent prognostic factor for recurrence-free (p=0.013)andcancer-specificsurvival( p=0.035). Conclusion: Our data suggests that CAP2 expression is upregulated in aggressive histologic subtypes of epithelial ovarian cancer and serves as a novel prognostic biomarker for clinical outcome.