A quantitative structure–activity relationship (QSAR) analysis has been performed on a data set of 42 aryl alkenyl amides/imines as bacterial efflux pump inhibitors. Several types of descriptors including topological, spatial, thermodynamic, information content and E-state indices have been used to derive a quantitative relationship between the efflux pump inhibiting activity and structural properties. Algorithm based on genetic function approximation method of variable selection was used to generate the model. Statistically significant model (with r 2 =0.87) was obtained with the descriptors like radius of gyration and heat of formation besides E-state indices, AlogP atom types and solvent accessible charged surface area playing an important role in determining the activity of the compounds against bacterial efflux pump. The model was also tested successfully for external validation criteria. The model is not only able to predict the activity of new compounds but also explained the important regions in the molecules in quantitative manner.