We developed a new software named TEICTDM based on the Bayesian estimation utilized in the therapeutic drug monitoring (TDM) of teicoplanin, a glycopeptide antibiotic, for the estimation of individual pharmacokinetic parameters. Therefore, it is necessary to input more than one plasma concentration(s) determined in individual patient. Individual pharmacokinetic parameters were calculated by a least squares methods, MULTI2 (BAYES). Two-compartment model was applied to determine individual pharmacokinetic parameters in male healthy volunteers in Japan, and the relationship between clearance of teicoplanin and creatinine clearance in adult patients with various degrees of renal impairment in Europe was used. A series of work from data input to graph drawing or printing of results could efficiently carried out with the best of use of this software, suggesting that this software is now available in clinical practice.