Eighteen patients with primary papillary serous carcinoma of the peritoneum (PPSCP) were treated at the Department of Obstetries and Gynecology of the University of Graz between 1980 and 1996. Primary tumours from other sites, particularly the pancreas and ovary, had been excluded. Because of extensive spread of the disease particularly in the upper abdomen, seven of the 18 patients (38%) underwent exploratory laparotomy only. Median overall survival time was IO months (range 1-28+). This figure reflects the extent of spread of the disease at diagnosis on one hand, and that optimal cytoreductive surgery (residual disease ≤ 2 cm) was possible only in six of the 18 patients (33%) on the other. The six patients with optimal cytoreduction had a better survival (range 4+ to 28+ months) than those who underwent less radical surgery. These data indicate, that, similar to primary ovarian cancer, the amount of residual disease may be an important prognostic factor in patients with PPSCP.