A switch from protease inhibitors (PIs) to raltegravir (RAL) will be effective virologically and immunologically. Moreover, it will be associated with significant improvements in the lipid profile in HIV patients with undetectable viremia on PIs. In this setting, RAL once a day (QD) will perform as well as RAL twice a day (BID).

Inclusion Criteria:

• HIV1 sero-positive using standard diagnostic criteria
• Plasma viral HIV-RNA below 50 copies/ml within 180 days prior to randomization
• On therapy with protease inhibitors both ritonavir-boosted or un-boosted for at least 6 months prior to study entry

Exclusion Criteria:

• Pregnancy or breast feeding
• Prior use of Integrase inhibitors
• Alcohol or substance abuse if according to the investigator opinion would interfere with compliance
• UIse of investigational medications within 30 days before study entry or during the trial