Continuation of failed highly active antiretroviral therapy regimens can lead to the accumulation of mutations that may limit options for second-line treatment. We studied the pattern of drug resistance mutations among 138 Indian patients who experienced failure of nonnucleotide reverse-transcriptase-containing first-line highly active antiretroviral therapy. This study demonstrates a high frequency of drug resistance mutations in human immunodeficiency virus-infected Indians who experience immunologic treatment failure and suggests the need for viral load monitoring.