We evaluated a single-class quadruple nucleoside/nucleotide regimen in a 96-week prospective one-arm pilot study in adult HIV-infected naive patients with CD4 >100 cells/microl. Standard zidovudine/lamivudine/abacavir and tenofovir doses were given. Virologic efficacy was evaluated by intent-to-treat (ITT), switch = failure and on-treatment (OT) analyses. A total of 54 patients were included (median CD4 count 254 cells/microl, VL 79,706 copies/ml). A median drop in VL of 2 log at 14 days and >3 log since week 12 was observed. A total of 34/54 (63%) patients (ITT) and 34/39 (87%) patients (OT) had VL <50 copies/ml at 96 weeks. Four (7%) patients switched therapy due to adverse events, 5 (9%) had virologic failure, and 1 died. Similar efficacy results were observed irrespective of baseline VL (> or <5 log) or CD4 cells (> or <250/microl). A median CD4 gain of +223 cells/microl was achieved. K65R + 41L + 219Q were detected in one patient at virologic failure. Only two patients presented fat loss on clinical evaluation. A decrease in total cholesterol (p = 0.007) and LDLc (p = 0.016) was observed. Our data suggest that zidovudine/lamivudine/abacavir plus tenofovir is a simple, effective, and well-tolerated NNRTI/PI-sparing regimen, even for patients with high viral loads. Larger trials comparing this option with standard initial antiretroviral regimens should be conducted.