Many communities1 throughout the world are battling an AIDS epidemic where sexual intercourse is a major mode of transmission. Until a vaccine is developed, one goal of HIV/AIDS prevention programs is to reduce the future impact of AIDS by influencing present sexual behaviour. Identifying those factors related to the adoption and maintenance of safer sex is one goal of HIV/ AIDS prevention research. Once identified, HIV/AIDS prevention programs can develop interventions with individuals, partners and communities that emphasize those factors related to behaviour change. The purposes of this chapter are to demonstrate that time is a crucial concept in understanding sexual behaviour, and to suggest ways that increase the effectiveness of interventions by considering the place of time.