The various QSAR models have been developed to predict the activities in terms of log 1/C for 34 HEPT (1-[(2- hydroxyethoxy) methyl]-6-(phenylthio)-thymine) derivatives anti-HIV compounds with the help of physiochemical descriptor Molar refractivity (MR), Molar Volume (MV), Parachor (Pc) and quantum chemical descriptor HOMO energy, LUMO energy, absolute hardness, Softness, Chemical Potential and Electronegativity. The parameter adopted in this calculation is the semi-empirical PM3 based. The QSAR model sixth provides a good arrangement between Obs log 1/C & predicted activity.