The pharmacokinetic data of amikacin were determined after a 1 hr constant infusion with a dosage of 7.5 mg/kg body weight in 12 healthy test subjects. Microbiological bioassay was performed by the agar diffusion test. After the infusion, the mean amikacin serum concentration was 37.5 mug/ml and, 8 hours later, decreased to an average of 1.3 mug/ml. The biological half-life amounted to a mean of 114.2 min, the area below the concentration-time-curve was calculated to an average of 140.4 hr - mug/ml. The renal clearance of amikacin was determined during a 4 hr constant infusion in 3 test individuals; the average clearance was 84.3 ml/min - 1.73 m2. 38 patients with severe bronchopulmonary, urinary and peritoneal infections were treated with an average daily dose of 10-15 mg of amikacin per kg body weight during a mean period of 10 days. 32 patients showed clinical improvement, 17 of them with complete elimination of the pathogenic bacteria.