A set of nineteen Pyrazinecarboxamides derivatives with herbicidal activity was subjected to the two dimensional quantitative structure activity relationships studies using Vlife molecular drug design 3.0. Drug Designing module contain various combinations of thermodynamic, electronic, topological and spatial descriptors. Pyrazinecarboxamides taken as the lead molecule and QSAR model developed using multiple regression approach. For each set of descriptors, the best multilinear QSAR equations were obtained by the stepwise variable selection method using leave-oneout cross-validation as selection criterion. Logarithmic inverse value of IC50 was taken as dependent variable and H-Acceptor Count and T_T_O_7 topological parameter was taken as independent variable. The best QSAR model (r2 = 0.85, Fisher test value F=29.26, r2 se = 0.12) has acceptable statistical quality and predictive potential as indicated by the value of cross validated squared correlation coefficient (q2=0.73). From the build model it seems to be clear that H-Acceptor Count and T_T_O_7 topological parameter contribute negative biological activity. Thus this validated model brings important structural insight to aid the design of novel herbicidal agents.
