The aim of this study was to assess the correlation between the estimated adherence of HIV-1 infected patients with antiretroviral (ARV) therapy failure and drug-resistant mutations. We studied 40 patients with virological and immunological ARV-therapy failure. In order to assess the adherence of patients we used the SERAD questionnaire. Genomic sequencing of the HIV-1 pol gene was performed. 100% adherence was reported by 27 patients (67.5%) (adherent patients). Multivariate analysis showed that only baseline and nadir CD4+ counts maintained a significant correlation with the adherence. For PR and NNRTI mutations, we did not find any difference between the two groups of patients. Baseline NRTI mutations were higher in adherent patients than in non-adherent patients (p<0.05). No differences were found between plasma mutations and PBMC mutations. The authors conclude that genotypic resistance mutations were found in the majority of patients with ARV-therapy failure despite a good self-reported adherence to therapy. Adequate adherence to therapy is not the only key factor in viral suppression.