To elicit patients' preferences for HIV/AIDS treatment characteristics in Colombia.A best-worst scaling case was used to provide a ranking of 26 HIV/AIDS treatment characteristics that were similar to a previous study conducted in Germany. In each choice task, participants were asked to choose the most important and the least important treatment characteristics from a set of five from the master list. Using the Hierarchical Bayes method, relative importance scores were calculated. Sub-group analyses were conducted according to sex, education, source of infection, symptoms, and age.A total of 195 patients fully completed the questionnaire. The three most important characteristics were "drug has very high efficacy" (relative importance score [RIS] = 10.1), "maximum prolongation of life expectancy" (RIS = 9.7), and "long duration of efficacy" (RIS = 7.4). Sub-group analysis showed only three significant (but minor) differences between older and younger people.This study suggests that treatment characteristics regarding efficacy and prolongation of life are particularly important for patients in Colombia. Further investigation on how patients make trade-offs between these important characteristics and incorporating this information in clinical and policy decision-making would be needed to improve adherence with HIV/AIDS medication.