The clinical significance and prognosis of culture-negative neutrocytic ascites in cirrhotic patients is a controversial topic. In the present study, the clinical and humoral presentation and the short- and long-term prognosis were analyzed in 36 patients with cirrhosis and culture-positive spontaneous bacterial peritonitis and in 28 patients with cirrhosis and ascitic fluid polymorphonuclear count greater than 250/mm3, a negative ascitic fluid culture, and without previous antibiotic therapy. On admission there were no significant differences between groups related to age, sex, alcoholism, fever, abdominal pain, serum albumin, serum urea, serum creatinine, Child-Pugh score, polymorphonuclear count, and total protein concentration in ascitic fluid. A greater frequency of positive blood culture was found in patients with spontaneous bacterial peritonitis (15/21 vs 2/18) (P < 0.001). Mortality during the first episode was 36% in patients with spontaneous bacterial peritonitis and 46% in patients with culture-negative neutrocytic ascites (NS). Mortality during follow-up was high and survival probability at 12 months was 32% in spontaneous bacterial peritonitis and 31% in culture-negative neutrocytic ascites. The probability of recurrence at 12 months was 33% in spontaneous bacterial peritonitis and 34% in culture-negative neutrocytic ascites. Our results show that spontaneous bacterial peritonitis and culture-negative neutrocytic ascites are variants of the same disease with a high mortality and poor prognosis.