To assess the efficacy and safety of maraviroc (MVC) administered once-daily in routine clinical practice. A retrospective multicenter study (27 centers in Spain) was conducted. Data were collected from the records of patients starting a regimen with MVC. Laboratory and clinical data were recorded every 3 months the first year and every 6 months thereafter. Data are presented as median and interquartile range. Among 667 patients treated with MVC, 142 (21.3%) received MVC once-daily: 108 (76.1%), 150mg and 34 (23.9%), and 300 mg. Age was 47 (42-45) years, there were 76.1% men, and 81 (57%) patients had baseline HIV-RNA < 50 copies/mL. Viral tropism was R5 in 118 (83.1%) patients. Reasons for prescribing MVC: salvage therapy (36.6%), drug toxicity (31.2%), simplification (16.9%), and immunodiscordant response (7.1%). Median follow-up was 13 (9-16) months. In 95.8%, a PI/r was part of the regimen (67% on dual therapy). At months 12 and 24, 73.3% and 68.2% of patients had HIV-RNA < 50 copies/mL, respectively (p=.041 and p