A better understanding of the pharmacokinetics of pefloxacin in human bone is warranted by the efficacy of this drug in the treatment of bone and joint infections. Surgical bone samples were taken at 30 mn, 1h, 6h, 12h and 24 h after the administration of a single 800 mg intravenous dose of pefloxacin over 1 hour for 26 patients who underwent surgery in an orthopedic surgery ward. Drug concentration was measured by a microbiological method (extraction of the antibiotic in buffer or with chloroform). Up until the 24th hour, in 25/26 cases, the bone levels were superior to 2 mg/l (the critical concentration of pefloxacin) in cortical as well as in spongy bone. Our study reveals a good diffusion of pefloxacin in bone, results which support the idea that this antibiotic may be prophylactically effective in orthopedic surgery.