A retrospective analysis of clinical data extracted from hospital records of 145 patients who had had primary surgical treatment for endometrial cancer in Queen Mary Hospital, Hong Kong, from 1987 to 1993 was performed to study the prognostic significance of positive peritoneal cytology. Positive peritoneal cytology was found to be associated with poor prognostic factors such as deep myometrial invasion, high grade tumor, extrauterine spread and lymphovascular permeation. By univariate analysis, all the poor prognostic factors were found to be significant in affecting survival. These included age above 65, nonadenocarcinoma histology, deep myometrial invasion, positive cytology, extrauterine involvement and lymphovascular involvement. By multivariate analysis, only histology and extrauterine involvement remained significant. In patients with positive cytology, 61.1% had extrauterine involvement at initial presentation. Patients who had positive cytology and extrauterine disease had the shortest survival. The survival was independent of cytology result when the tumor was confined to the uterus.