The track records of the use of anti-methicillin-resistant Staphylococcus aureus agents (anti-MRSA agents) in a 5-year period (2001.4-2006.3) were collected, and cases in which anti-MRSA agents were used for >4 days were selected. In each case, the results of laboratory data and bacterial examination before and after administering the anti-MRSA agents were investigated retrospectively. In addition, it was also investigated in each case whether therapeutic drug monitoring (TDM) was carried out. It was observed that the number of patients treated with anti-MRSA agents and the total dose of anti-MRSA agents used tended to increase over time, except for arbekacin sulfate. It was, however, shown that treatment with anti-MRSA agents resulted in significant decreases in body temperature, C-reactive protein, and white blood cell counts. Bacterial examination was conducted in 75.6% of the patients treated with anti-MRSA agents, with MRSA being detected in 72.4% of the cases examined. On the other hand, TDM was also conducted in 60% of the cases, but this was at a lower percentage than that of the other examinations. Quantitative bacterial examination after treatment with anti-MRSA agents indicates that TDM can be considered important for the appropriate use of anti-MRSA agents.