The efficacy and pharmacokinetics of latamoxef were evaluated during initial therapy of bacteriologically proven bone and joint infections in children. Pharmacokinetic evaluation revealed no significant difference in latamoxef biodisposition after the first dose or at steady state. Peak serum concentrations exceeded 140 mg/l and 8-hour trough concentrations averaged 6.5 mg/l. The patients were infected with a variety of gram-positive and gram-negative pathogens. All were sensitive to readily achievable serum concentrations of latamoxef; moreover, the serum concentration remained above the MIC of the most resistant organism for at least 7 h after each dose. All patients responded favorably to initial therapy and there have been no relapses in more than 2 years of clinical follow-up.