Etravirine demonstrates activity against NNRTI-resistant HIV-1 but its efficacy depends on the number of etravirine resistance-associated mutations (RAMs). This study aimed to evaluate the role of etravirine in the second regimen in a resource-limited setting. Genotype resistance assay was conducted in a cohort of HIV-infected patients who experienced virological failure from an initial NNRTI-based regimen. We focused on etravirine-RAMs previously described: V90I, A98G, L100I, K101E/P, V106I, V179D/F, Y181C/I/V, and G190A/S. Frequency and predicting factors for <or=2 etravirine-RAMs were evaluated. There were 158 patients with a median duration of ART prior to failure of 22 months. The median CD4 cell count and HIV-1 RNA at the time of virological failure were 173 cells/mm(3) and 4.1 log copies/mL, respectively. Of all, 75.3% of patients were predicted to have <or=2 etravirine-RAMs. From logistic regression, there was no clinical factor to predict etravirine susceptibility. Patients with <or=2 etravirine-RAMs had lower rates of K65R (3.4% vs 17.9%, p=0.005), Q151M (5.9% vs 20.5%, p=0.012), and multi-NRTI resistance mutations (16.8% vs 48.7%, p<0.001) when compared to patients with >2 etravirine-RAMs. Etravirine may have activity for using in the second regimen in most patients in resource-limited setting who fail an initial NNRTI-based regimen. Genotype testing is needed to identify this group. Some of these patients, indicated by genotype results, may be able to use etravirine plus 2 active NRTIs for second ART regimen. This strategy may be an option for patients who cannot afford or tolerate protease inhibitor. Prospective study to evaluate this strategy should be conducted in resource-limited setting.