This protocol describes a prospective, randomized, open-label, multicenter study to evaluate the safety and efficacy of switching from fixed dose abacavir (ABC)/lamivudine (3TC) to fixed dose emtricitabine (FTC)/tenofovir disoproxil fumarate (TDF) in virologically suppressed, human immunodeficiency virus type 1 (HIV-1) infected subjects maintained on a ritonavir-boosted protease inhibitor (PI/r)-containing antiretroviral (ARV) regimen. Duration of treatment is 48 weeks.