The concentrations in serum, cancellous and cortical bones of dibekacin sulfate were measured in 16 cases. Dibekacin sulfate rapidly penetrates into bone. The peak concentration in serum and cancellous bone is reached within 1 hour after intramuscular injection and the concentration in cancellous bone parallels that in serum. The concentration in cortical bone increases with time. Cancellous bone has higher concentration than cortical bone. Dibekacin sulfate is suitable for prevention of infection in orthopaedic surgery, because it maintains a bactericidal level in bone for enough time.