The purpose of this investigation was to determine pharmacokinetic parameters of gentamicin using linear least square regression(LLSR) and Bayesian analysis in Korean normal volunteers and appendicitis patients. Nonparametric expected maximum(NPEM) algorithm for population pharmacokinetic parameters was used. Gentamicin was administered every 8 hours for 3 days by infusion over 30 minutes. The volume of distribution(V) and elimination rate constant(K) of gentamicin were $0.215pm0.0562,;0.226pm0.0325L/kg;and;0.339pm0.0443,;0.357pm0.0243hr^{-1}$ for normal volunteers and appendicitis patients using LLSR analysis. Population pharmacokinetic parameters, VS and KS were $0.228pm0.0614L/kg;and;0.00356pm0.00041(hr{cdot}mL/min/1.73m^2)^{-1}$ for appendicitis patients using NPEM algorithm. The V and K were $0.232pm0.0568L/kg;and;0.337pm0.0385hr^{-1}$ for appendicitis patients using Bayesian analysis. There were no differences in gentamicin pharmacokinetics between LLSR and Bayesian analysis.