HIV protease inhibitors were first invented between 1989 and 1994 by researchers working for the pharmaceutical companies of Hoffmann- La Roche Inc. (in Nutley, New Jersey), Abbott Laboratories and Merck & Co., Inc. HIV protease inhibitors are used in the treatment of patients with AIDS and were considered the first breakthrough in over a decade of AIDS research. Currently, there are five HIV protease inhibitors approved by FDA for the treatment of HIV infection. These drugs work at the final stage of viral replication and attempt to prevent HIV from making new copies of itself by interfering with the HIV protease enzyme. As a result, the new copies of HIV are not able to infect new cells. Occurrence of protease along with structural properties, classification of inhibitors like Saquinavir, Ritonavir, Indinavir, Nelfinavir etc and life cycle of virus confirm the role of protease inhibitor. Other parameters like adverse effect, application, structure activity relationship and dose regime shows need of medication for person suffering from HIV virus.