Aims : In this study in cirrhosis patients having spontaneous ascites infection (SAI) the investigation of the activity of cefepime being a fourth generation cephalosporin was aimed. Method: 19 patients diagnosed as cirrhosis and having acid infection were taken into the study. Cefepime doses were given to all patients having SAI by adjusting according to the clearance of creatinine, in intervals of 12 hours, in 2 gram as parenterally. Cell counting was made in acid liquid on the 1st, 3rd and 5th days. In the patients who had reproduction in acid liquid culture, antibiogram was made with cefepime and other antibiotics. Result: Age average of patients was 55 years (between 42-73 years). Cirrhosis was secondary to hepatitis B virus infection in 10 patients, to hepatitis C virus infection in 7 patients and to autoimmune hepatitis in 2 patients. On the first day the average cell number in the ascites was 5077/mm3 (between 530-12400/mm3), PMNL number was 3861/mm3 (between 320-9600/mm3). On the third day the average cell number in the ascites was 1847/mm3 (between 300-7680/mm3) and PMNL number was 1025/mm3 (between 120-3840/mm3) (p<0.001). Fifth day ascites liquid the average cell number was 548/mm3 (between 160- 1600/mm3) and PMNL number was 267/mm3 (between 80-620/mm3) (p<0.001). The cefepime resistance in antibiogram was observed only on one patient against E.coli strain. Conclusions: Cefepime, which is a fourth generation cephalosropin, was found out effective in SAI developing on cirrhotic ground.