The current study examines predictors of HIV test acceptance among emergency department patients who received an educational video intervention designed to increase HIV testing. A total of 202 patients in the main treatment areas of a high-volume, urban hospital emergency department used inexpensive netbook computers to watch brief educational videos about HIV testing and respond to pre-postintervention data collection instruments. After the intervention, computers asked participants if they would like an HIV test: Approximately 43% (n = 86) accepted. Participants who accepted HIV tests at the end of the intervention took longer to respond to postintervention questions, which included the offer of an HIV test, F(1, 195) = 37.72, p < 0.001, compared with participants who did not accept testing. Participants who incorrectly answered pretest questions about HIV symptoms were more likely to accept testing F(14, 201) = 4.48, p < 0.001. White participants were less likely to accept tests than Black, Latino, or "Other" patients, ?[superscript 2](3, N = 202) = 10.39, p < 0.05. Time spent responding to postintervention questions emerged as the strongest predictor of HIV testing, suggesting that patients who agreed to test spent more time thinking about their response to the offer of an HIV test. Examining intervention usage data, pretest knowledge deficits, and patient demographics can potentially inform more effective behavioral health interventions for underserved populations in clinical settings.