The behaviors of dibekacin after three administration methods to rabbits and dogs were pharmacokinetically analysed. 1) In both rabbits and dogs, the pharmacokinetic constants for the intravenous constant infusion and intramuscular injection were similar to each other, and the serum levels after the intravenous constant infusion for 1 hr were similar to those after the intramuscular injection except the peak time. 2) In both rabbits and dogs, Vd increased with the dose and a linear correlation was noted between log Vd and log (dose). 3) The tissue concentrations of dibekacin decreased with the decrease in the serum concentration. 4) A correlation equation, log T 1/2 = 0.194 . log B + 1.128, was obtained, where T 1/2 and B represent the biological half-life of dibekacin and the body weight of animals, respectively. It was suggested that the pharmacokinetic behaviors of dibekacin in human beings can be predicted from the results of the animal experiments.