BACKGROUND The present study aimed to address the suspected deficiency in the level of understanding of HIV/AIDS among clinical and pre clinical dental students at the University of Jordan. In this cross-sectional study, structured questionnaires were distributed to fifth year dental students (n = 121) and to third year dental students (n = 144) in the academic year 2008/2009. RESULTS Significantly higher percentage of fifth-year students compared to third-year students felt that the teaching they received on cross-infection precautions and barrier dentistry was adequate (P < 0.001). Majority (84.2%) of fifth-year students were aware that individual carrying anti-HIV antibodies to be an HIV carrier, only 57.7% of third-year students were aware of this fact (P < 0.001). Majority recognized the association between Kaposi sarcoma, oral candidiasis and hairy leukoplakia with HIV/AIDS but knowledge of the association between HIV/AIDS with less frequent lesions was inadequate.Significantly higher proportion of third-year students compared to fifth-year (39.2% vs. 26.3%) thought that HIV patients should be referred to other centers or support groups for treatment (P = 0.04). CONCLUSIONS The level of knowledge of Jordanian dental students about HIV and AIDS was generally acceptable; there were inadequacies, however, in their understanding regarding some aspects of AIDS epidemic which demands that dental school curriculum needs some improvement.