There are many drugs available in the market for treating typhoid infection, but the emergence of multi-drug resistant strain of Salmonella typhi (S.typhi) has necessitated the exploration and development of newer structural moiety of Schiff bases as anti-S. typhi agents owing to their enormous inhibitory activity against this bacterium. In this present study, a Genetic function approximation (GFA) QSAR analysis of some selected Schiff bases with anti-S. typhi activity was performed using Semi-empirical (Pm3) derived OD,1D, 2D and 3D descriptors resulting in the generation of three statistically significant models from which an octa-parametric model was selected as the most robust model with R2 = 0.8589, R2adj = 0.8155, Q2 = 0.7437,R2 - Q2 = 0.1152, r2 – r02 / r2 =0.00, r2 – r‘02 / r2 = 0.0263. The optimization model hinted the dominant influence of the size descriptor ETA-Eta-B (Branching index EtaB relative to molecular size) on the observed anti-S.typhi activity of Schiff bases. It is envisaged that the QSAR results identified in this study will offer important structural insight into designing novel anti-S.typhi drugs from Schiff bases.