The case of a 42-year-old woman with no previous disease admitted for abdominal pain and ascites is presented. Analysis of the ascitic fluid demonstrated high concentrations of amylase with normal lipase. The diagnosis of peritoneal mesothelioma was obtained by laparotomy. This association has not been previously described. The authors suggest that this diagnostic possibility should be considered in patients without pancreatic disease and high amylase levels in ascitic fluid.