In this study we compared the efficacy and safety of isepamicin versus amikacin at a dose of 7.5 mg/kg i.v. q12h for 10-14 days in children with pyelonephritis. Sixteen children were enrolled in the study; ten received isepamicin and six amikacin. Urine cultures grew Escherichia coli in all patients. All patients were treated successfully with either isepamicin or amikacin. Clinical and bacteriological response rates were 100% for both groups. No adverse events occurred. Peak serum levels ranged from 9.05 to 30.70 mg/l (median: 16.165) and from 12.20 to 25.90 mg/l (median: 19.05) for isepamicin and amikacin, respectively. Trough serum levels ranged from 0.11 to 3.20 mg/l (median: 0.75) and from 0.1 to 2.1 mg/l (median: 0.655), respectively. Isepamicin was shown to be as effective and safe as amikacin in the treatment of children with pyelonephritis and might prove an advantageous alternative in areas with high incidence of resistance to other aminoglycosides.