Ovarian serous tumors make up about one-fourth of all ovarian tumors. There is a spectrum of proliferation and cellular atypia in these tumors with benign serous cystadenoma, borderline tumors, and low grade or type I serous carcinoma at the lower end and type II or high-grade serous papillary cystadenocarcinoma at the higher end. Fascin is a globular actin cross-linking protein involved in cell motility that has been shown to be upregulated in many human neoplasms and associated with the aggressiveness of malignancy. The aim of this study was to investigate fascin expression in serous tumors of ovary and to evaluate its relationship with the aggressiveness of tumor. Sections from a total of 66 serous tumors of ovary were collected including 26 serous carcinomas, 20 borderline serous tumors, and 20 benign serous cystadenomas. Ten benign ovaries with inclusion cysts were used as controls. Sections were immunostained with fascin. Fascin expression was significantly increased in borderline (13/20, 65%) and malignant serous tumors (22/26, 84%) compared with benign serous cystadenoma (0/20) (P<0.001). There was increased quantitative expression of fascin in carcinoma compared with borderline tumors (diffuse versus patchy). Fascin expression also correlated well with the tumor grade in serous carcinoma cases with 8/12 (66%) of grade I/II tumors staining positive compared with all 14 (100%) of grade III tumors showing fascin expression (P<0.05). Our findings suggest that upregulation of fascin plays a role in increasing aggressiveness of serous ovarian tumors and could potentially be a molecular therapeutic target and a prognostic marker.