Background Although there have been studies examining HIV knowledge among college population, current study is the first providing comparable information on HIV knowledge in general and testing specifically via online surveys among black and white college students. Methods Blacks (N=222) were recruited from 15 historically black college and universities (HBCUs) and whites (N=335) from a traditionally white institution. Results The majority of the students were aged 18–24 years. Reliability of the overall knowledge scale showed good internal consistency for both samples (alpha=0.70). Students overall scored higher on items related to HIV/AIDS in general (81.5% correct) and lower on items related to HIV testing (71.6% correct), with no significant difference between groups. However, blacks rated significantly higher on their subjective (or “perceived”) HIV general knowledge (item mean 3.55 vs. 3.26) and testing specific knowledge (item mean 3.13 vs. 2.54) (p<0.01). Results showed that blacks were 6.9 times more likely to have been tested for HIV. Subjective HIV testing knowledge (OR=2.9) and nonheterosex-ual orientation (OR=3.2) were also significant predictors to prior testing behavior. Conclusions The knowledge scale assessed via the Internet demonstrated satisfactory reliabilities among diverse college students. Data showed that HBCU black students perceived significant higher knowledge levels, despite results showing similar knowledge scores as white students. Results have implications on HIV prevention among students attending their race/ethnic dominant institutions.