The concentrations of gentamicin and cefotaxime (claforan) in the humor of the anterior chamber and vitreous body of the eye were estimated in the study on the pharmacokinetics of the antibiotics in rabbits. The antibiotics were administered intravitreally in single doses. It was shown that the residence time of the antibiotics in the therapeutic concentrations in the eye cavity was 48 hours. Cefotaxime proved to be the most efficient agent in the prevention and treatment of postoperative endophthalmitis.