There are few data on the clinical and virological factors associated with the virological response (VR) of maraviroc (MVC) in clinical practice. This study aimed to identify factors associated with the VR to MVCcontaining regimens in 104 treatment-experienced but CCR5 inhibitor-naive HIV-1 patients. VR was defined at month 3 (M3) as HIV-1 RNA viral load (VL) < 50 copies/ml. The impact on VR of age, sex, baseline tropism, HIV subtype (B vs. non-B), nadir CD4 cell count and CD4 cell count, baseline VL, genotypic susceptibility score of treatment, once or twice daily treatment, presence of raltegravir in optimized background therapy, and MVC concentrations was investigated. Median baseline VL was 3.3 log 10 copies/ml (range 1.7-6.0 log 10 copies/ml) and CD4 cell count was 299 cells/mm 3 (range 7-841 cells/mm 3 ). At M3, 53.8% of patients were responders. In univariate analysis, a better efficacy of the MVC-containing regimen was associated with a high CD4 cell count ( p = 0.0069) and there was a trend for low baseline VL, high nadir CD4 cell count, and HIV subtype (B versus non-B). Only low baseline VL remained significantly associated with better VR in the multivariate analysis. This study demonstrated a VR of an optimized antiretroviral treatment including MVC in clinical practice similar to that observed in clinical trials. The factors associated with VR were higher baseline CD4 cell count in univariate analysis and lower baseline VL in multivariate analysis.