The present study aims to compare efficacy, side-effects, and treatment adherence of three different treatment regimens given to antiretroviral naïve HIV-1 infected patients. Treatment will be initiated in accordance with the Swedish National Guidelines. In the twice daily (BID) arm (1), which could be considered as a standard regimen at present, lopinavir/ritonavir, is co-administrated with 2 nucleoside reverse transcriptase inhibitors (NRTIs) administrated BID. The first once daily (QD) arm (2) combines the protease inhibitor (PI) atazanavir/ritonavir with 2 NRTIs administrated QD, and in the second QD arm (3), the non nucleoside reverse transcriptase inhibitor (NNRTI) efavirenz is combined with 2 NRTIs administrated QD. All drugs used in the study are licensed in the participating countries and patients will be followed as in clinical practice. Patients could optionally, after informed consent, be followed with additional measurements of HIV-1 RNA after 1, 2, and 3 weeks of treatment to asses the kinetics of viral decline after initiation of treatment.

Inclusion Criteria:

• Male or female, aged 16 years of age
• HIV-1 infected as documented by a licensed HIV-1 antibody ELISA
• Ability to understand and provide informed consent
• Indication for antiretroviral treatment
• Antiretroviral naïve
• All clinical laboratory values not clinically significant

Exclusion Criteria:

• Subjects being pregnant
• Women of childbearing potential not practicing birth control
• Subjects with renal failure requiring dialysis
• Drug interactions with any of the study drugs that are not manageable
• Resistance to any of the study drugs