Data from a cohort of HIV-positive individuals who were antiretroviral naive at enrollment were analysed to estimate the probability of discontinuing the first highly active antiretroviral therapy (HAART) regimen, comparing protease inhibitor- and non-nucleoside reverse transcriptase-containing regimens. Of the 2002 individuals who began HAART, 857 (42.8%) discontinued their first regimen. No statistically significant difference was found in the time to discontinuation by specific type of regimen, either when considered overall or by specific reason.