Abstract: NONMEM program was applied for analyzing population pharmacoki netics/pharmacodynamics of magnesium sulfate in pregnancy induced hypertensive patients treated with thedrug.A 2-compartment Open medel with fast and slow consecutive intravenous infusion was used toestimate population pharmacokinetics from 60 patients,A 3-compartment model comprised an effectcompartment linked to the central compartment,sigmoid Emax effect model and parametric methedwere used to estimate population pharmacodynamic parameters from 26 patients. Serum magnesiumconcen trati on was determined by spectr ophotometric method ant it was adjusted with basic valuedetermined before dosage. The diastolic blood pressure lowering effect was chosen as index of effect ofcardiovascular response.The population pharmacokinetic parameters of magnesium sulfate were:the standard value of K₁₀(h^-1),K₁₂(h^-1),K₂₁(h^-1),and Vc(L·kg^-1)were estimated to be l.62,20.8,2.70,and27.0 , respectively.Their interindividual varibilities were estimated to be 25.70%,14.13%,24.33%,and 34.04%,respectively.The residual error of concentrations was 15.03%,Thepopulation pharmacedynamic parameters of magnesium sulfate were:the standard value of E_max(%),C_e(50)(μ· ml^-1),v,and K_eo(h^-1)were estimated to be 28.73,28.39,4.22,and 0.43.Theirinterindividual variability were estimated to be 56.32%,62.24%,33.47%and 42.76%. Theresidual error of effect was 28.54%.