Computational techniques are effective tools for aiding the drug design process. Computational chemistry can be used to predict physicochemical properties, energies, biding modes, interactions and a wide amount of helpful data in lead discovery and optimization. The interactions formed between a ligand and a molecular target structure can be represented by molecular interaction fields (MIF). The MIF identify regions of a molecule where specific chemical groups can interact favorably, suggesting interaction sites with other molecules. In this context the MIF theory has been extensively used in drug discovery projects with a variety of applications, including QSAR, virtual screening, prediction of pharmacokinetic properties and determination of ligand binding sites in protein target structures.