Fifty cases of malignant ascites were studied to determine what factors influenced outcome after peritoneovenous shunt. There were 36 women and 14 men. The five most common tumor types were colon, breast, gastric, pancreatic, and unspecified adenocarcinoma. Multivariate analysis between those patients surviving longer than 7 weeks (n = 20) and those who died in less than 7 weeks (n = 30) showed that women did uniformly better than men, even excluding the "female malignancies" (P less than 0.01). An elevated white blood cell count (WBC) and low platelets also were strong predictors of poor outcome (P less than 0.5 for difference in means between the two groups). Patients with pancreatic cancer and ascites fared poorly (80% mortality by 7 weeks) as did those with colon cancer (73% mortality by 7 weeks). By contrast, 50 per cent of the patients with breast and gastric cancer lived more than 7 weeks. Twelve patients had a LaVeen shunt placed, compared with 38 who had a Denver shunt. Fifty per cent of the La Veen shunts failed, with a mean time to failure of 69 days (P less than 0.01). Shunt failure, however, had no influence on overall survival.