The diffusion of Myocamicin in the prostatic tissue of patients undergoing prostatectomy after a single oral dose of 600 mg has been studied. The maximum concentration of antibiotic in the prostatic tissue and the serum peak are reached at the first hour with mean values respectively of 3.8 micrograms/g and 2.6 micrograms/ml. The concentrations of Myocamicin remain more elevated in the prostatic tissue compared with the serum levels, at the second, fourth and sixth hours. Myocamicin has shown itself to be an antibiotic with optimal capabilities of diffusion in the prostatic tissue, where it rapidly reaches good therapeutic concentrations.