The CCR5 chemokine receptor is expressed on a wide range of immune cell types and binding to this receptor mediates cellular entry by the majority of HIV isolates. Blocking viral entry via this receptor reduces the viral load in patients infected with HIV, suggesting that a CCR5 antagonist could become a key component in the treatment of HIV-compromised patients. A number of CCR5 antagonists are currently in clinical trials. This review details the status of leading agents and highlights recent advances in the development of new CCR5 antagonists.