Abstract: Vancomycin has been widely prescribed as the first-line antibiotic in the treatment of methicillin-resistant Staphylococcus aureus and other serious Gram-positive infections. Due to its large pharmacokinetic (PK) variability and narrow therapeutic range, it requires optimization of dosage to achieve target exposure. In this study, SmartDose, a decision support system for individualization of vancomycin dosage is developed using the maximum a posterior Bayesian estimation (MAPB) by the open-source language R combined with the population PK characteristics of vancomycin in Chinese patients. It provides initial design and adjustment of dose regimens based on the therapeutic drug monitoring (TDM) results, as well as a user-defined module to facilitate optimal vancomycin therapy. SmartDose has a high computational reliability, which is validated by NONMEM, the golden standard PK software. Meanwhile, SmartDose is established as a web-based application and its operational flexibility makes it an efficient tool for vancomycin dose optimization in routine clinical settings.