AIDS, the fatal disease, caused in human by the fast spreading human immunodeficiency virus (HIV), was detected in 1981. To check its rapid growth, affecting various parts of the world population, there are various FDA approved drugs, released in the market for treating AIDS. These belong to 5 different categories which differ in their mechanism of action. These are i) reverse transcriptase inhibitors, ii) protease inhibitors, iii) fusion inhibitors, iv) entry inhibitors and v) HIV integrase strand transfer inhibitors. These drugs are mostly used in a combination therapy, named as Highly Active Anti Retroviral Therapy (HAART), using 2 to 3 compounds in combination, for a more effective and beneficial treatment. However, none of the drugs can be considered ideal for curing the disease. A study of structural requirement for different types of anti-HIV activities may help in designing a suitable drug for AIDS.