New recommendations for vancomycin (VCM) dosages and dosing intervals for MRSA-infected pneumonia patients with various degrees of renal function impairment were established based on Japanese population pharmacokinetic parameters proposed by Yasuhara et al. in 1998. Based on individual creatinine clearance (CLcr), we proposed the optimum VCM dosages and dosing intervals so that the peak level of VCM (level at 1 h after the end of infusion) is maintained in the range of 25-40 microg/ml and the trough level is kept under 15 microg/ml. The recommended doses and intervals of VCM were as follows: 20 mg/kg every 12 h for CLcr of 80-100 ml/min, 18 mg/kg every 12 h for CLcr of 70 ml/min, 25 mg/kg every 24 h for CLcr of 50-60 ml/min, 22 mg/kg every 36 h for CLcr of 40 ml/min, and 18 mg/kg every 48 h for CLcr of 30 ml/min. Using the recorded pharmacokinetic parameters of VCM from eight patients with pneumonia who were admitted to Aoyama Second Hospital between November 1997 and January 2002, these recommendations were used in computer simulations for the eight patients, and the usefulness of these recommendations was confirmed.