This study was conduct prospective randomized study to compare efficacy of ciprofloxacin, 750 mg weekly,with norfloxacin, 400 mg daily, in prophylaxis of spontaneous bacterial peritonitis in cirrhotic patients.  From March 2005 to Jan 2006, 25 patients were randomized by block of four to receive prophylaxis antibiotic withnorfloxacin 400 mg daily (N group) or Ciprofloxacin 750 mg weekly (C group).  Both groups will follow up as outpatients monthly for 6 months.  There were no difference in baseline characteristic of both groups. Ascites fluid culture was positive 3/13 patients from norfloxacin group and 2/12 patients from ciprofloxacin group reported E.coli. Only 1/13 patient from ciprofloxacin group infected with Klebsiella  pneumoniaei. No serious adverse reaction reported from both groups. We concluded that there were no differences prophylaxis between ciprofloxacin group and norfloxacin group.