['To assess the perceptions of personal risk of acquiring HIV/AIDS infection among students of selected tertiary institutions in Osun State, Nigeria and to determine the correlates of perceptions of personal risk of infection.', 'The study employed a cross-sectional descriptive design. An interviewer-administered questionnaire was applied to the 405 study participants and correlates of perceptions of personal risk of HIV infection were evaluated using multiple logistic regression analysis, confidence intervals and odd ratios.', "Only 15% of the students perceived themselves to be at moderate-to-high risk of acquiring HIV infection compared with 85% who perceived themselves to be at little or no risk. Investigators' assessment of risk status of the participants revealed that 77% of the participants were actually at high risk of infection and only 23% at low risk. The sensitivity, specificity and negative predictive value of the students' self-perception of personal risk compared with their assessed risk were 7, 58 and 16%, respectively, with a Kappa statistic of 0.178. The only significant correlate of self-perception of personal risk was a recent symptom of sexually transmitted infections."] Do college students in Nigeria underestimate their risk of contracting HIV/AIDS infection?