AIM: To compare the efficacy and safety of single daily amikacin vs. cefotaxime in the 5-d treatment of spontaneous bacterial peritonitis (SBP).METHODS: Thirty-seven cirrhotic patients with SBP,19 in group A and 18 in group B, were studied. Group A received 1 g of cefotaxime every 6 h, and group B received 500 mg of amikacin qd. Both antibiotics were administered up to 5 d and the responses were compared.RESULTS: Infection was cured in 15 of 19 patients (78.9%) treated with cefotaxime and in 11 of 18 (61.1%)treated with amikacin. Four patients of the Cefotaxime group (21.1%) and five patients of the Amikacin group (27.8%) died. Two in each group (10.5% vs 11.1%)had renal impairment during study period. One in each group (5.3% vs 5.6%) may be considered to suffer from nephrotoxicity due to increased urinary β2-microglobulin concentration.CONCLUSION: In this study, single daily doses of amikacin in the treatment of SBP in cirrhotics were not associated with an increased incidence of renal impairment or nephrotoxicity. However, a 5-d regimen of amikacin is less effective than a 5-d regimen of cefotaxime in the SBP treatment.