The pharmacokinetics of vancomycin was retrospectively examined based on trough concentrations obtained during routine therapeutic drug monitoring to examine possible pharmacokinetic differences between adult Japanese cancer and non-cancer patients with various degrees of renal function. A total of 231 data points from 65 cancer patients and 41 non-cancer patients were collected, and patients' background, vancomycin dose, and vancomycin clearance estimated by an empirical Bayesian method were summarized. Regarding the patients' characteristics and clinical laboratory test data, no clear differences were found between the two groups. The relationship between vancomycin clearance and creatinine clearance were similar between the groups, suggesting little effect of malignancy on vancomycin clearance. After the sub-group comparisons regarding fluid retention and cancer type, no clear differences were found in the vancomycin clearance versus creatinine clearance relationship. We conclude that the initial dose of vancomycin should not necessarily be adjusted for cancer patients. For individualized vancomycin-based therapy, dose adjustment at the appropriate time is important according to information from routine therapeutic drug monitoring and clinical laboratory tests, and to observations of the efficacy, nephrotoxicity, and other conditions in each patient.