Objective. The purpose of this study was to investigate the characteristics and infection control practices of dentists in Mexico City in relation to their willingness to treat AIDS/HIV-positive patients. Study design. The population study encompassed Mexico City dentists who were selected according to a geographic criterion. A questionnaire was delivered personally to each participant, and multiple logistic regression was used for data analysis. Results. A total of 598 dentists participated in the study. The response rate was 99.3% (598/602). Seventy-four percent (444) of the dentists said they would be willing to treat AIDS/HIV-positive patients. Among the variables associated with the prediction of willingness to treat these patients were glove-wearing patterns (odds ratio, 2.39; confidence interval, 1.4-4.2), types of available sterilization equipment (odds ratio = 2.42; confidence interval, 1.4-4.1), fear of losing non-AIDS/HIV-positive patients (odds ratio = 4.28; confidence interval, 2.3-8.4), and risk perception of HIV transmission (odds ratio = 2.66; confidence interval, 1.5-4.9). An interaction was found between perception of risk of HIV transmission and increase in costs (odds ratio = 3.35; confidence interval, 1.3-8.9). Conclusions. Approximately 26% of the Mexico City dentists included in the study were not willing to treat AIDS/HIV-positive patients. Educational programs aimed at misperceptions appear to be warranted.