Antiviral therapy has in the past met with limited success and only a few antiviral drugs have been available. The human immunodeficiency virus (HIV) epidemic has created an urgent need for the development of antiviral therapy against this infection. HIV replication offers several targets for inhibitory compounds, the foremost presently being the HIV reverse transcriptase and protease enzymes. Despite the short time since the beginning of the epidemic, 3 nucleoside analogue drugs (zidovudine, didanosine and zalcitabine) which act at the reverse transcriptase site are already licensed for use against HIV, and others (stavudine, alovudine and 3-TC) are still under clinical evaluation. Part II of this article discusses non-nucleoside reverse transcriptase inhibitors undergoing investigation, protease inhibitors, and compounds active against various other targets in HIV. Treatment guidelines are also provided in Part II.