 This pilot study will provide data on the safety and efficacy of the combination of Raltegravir RAL 400mg BID Atazanavir ATV 300 mg BID in Antiretroviral ARV-experienced subjects that have a suppressed HIV viral load on a Ritonavir RTV boosted Protease Inhibitor PI based regimen who are then switched to a regimen of RAL 400mg BID ATV 300mg BID. 