An excellent example in the field of rational drug design is the discovery and development of more than a dozen drugs for the treatment of AIDS. The major targets for the development of new chemotherapeutic agents are Reverse Transcriptase and Protease, the enzymes encoded by HIV-1. The introduction of HIV-1 protease (HIV-1 PR) inhibitors, in particular, has drastically decreased the mortality and morbidity associated with AIDS. The inhibition of this enzyme results in production of immature and noninfectious virions. In the present review, a comparative quantitative structure activity relationship (QSAR) study of various peptidomimetic and non-peptidomimetic molecules investigated for their inhibitory activity has been reported. Among the various physicochemical properties studied, hydrophobicity, steric and electronic interactions are found to play important role in binding to the receptor.