Adolescents' social relationships have the potential to enhance or impede the successful development of their heterosexual relationship, thus, the need to examine the relationship between HIV/AIDS awareness and dating behaviour among undergraduate students. The participants in the study were one thousand six hundred undergraduates (1600: M=800 and F=800) randomly selected from eight universities in South-western part of Nigeria, in the age range 16 to 30 years old. The AIDS Awareness/ Attitude Scale (AAS) and Dating Behaviour Questionnaire (DBQ) were used to collect data. The data were analyzed with Statistical Package for Social Sciences (SPSS) with emphasis on simple percentages, Multiple Regression Analysis, and Analysis of Variance (ANOVA). The results confirm that HIV/AIDS awareness account for a significant two percent (2%) variance in university students' dating behaviour. The implication of the result for understanding the heterosexual behaviour of undergraduates and minimizing their indecent relationships were discussed and recommendations made accordingly.