To determine whether positive peritoneal cytology is an independent poor prognostic factor in patients with endometrial carcinoma the records of 381 patients were reviewed. Positive peritoneal cytology was found in 24 of 381 (6.3%) patients. In clinical stage I disease, 16 of 322 (5.0%) patients had positive peritoneal cytology. Patients with positive cytology were more likely to have higher-grade tumors and extrauterine disease at the time of surgery (45% vs 2.3%) than were patients with negative cytology. Five-year survival was significantly less for patients with positive cytology than negative (50% vs 81.2%). For patients with surgical stage I disease (no extrauterine spread at surgery) there was no significant difference in 5-year survival between groups with positive and negative cytology (80% vs 86.3%). The majority (70.8%) of patients with endometrial cancer and positive peritoneal cytology have extrauterine disease at the time of surgery. Although overall 5-year survival is less for patients with positive cytology, when other risk factors are controlled for, there is no difference in survival for patients with no demonstrable extrauterine disease despite positive cytology. We conclude that positive peritoneal cytology is not an independent prognostic indicator for patients with endometrial cancer.