There is a limited number of antiviral drugs available for therapy. Many investigations and new analytical techniques have unraveled the development and progression of a viral infection. Nowadays there is a good understanding of the multiplication cycle of viruses, including the human immunodeficiency virus. 2. In this article the currently available antiviral drugs are presented arranged by their mode of action that can be understood by the multiplication cycle of the virus. 3. Clinical use and side-effects are discussed as well as place in current therapy. Some attention is paid on promising investigational antivirals.