The use of chiral compounds as pharmaceuticals and agrochemicals continues to increase, warranting numerical characterization of chirality in order to develop structure-activity relationship models involving these compounds. Enantiomers are identical in all scalar properties and, hence, are not differentiated by topological indices and 3-D descriptors. Three distinct measures of chirality were developed to discriminate diastereomers and enantiomers. The novel topological indices treat chirality as a continuous measure, and hence we prefer to call it the Relative Chirality Index (RCI). Application of RCI in developing SAR is illustrated with the repellency data for the diastereomers of picaridin and AI3-37220.