PIP: Event-specific analysis was used to identify relationships between condom use and situational variables in a sample of 244 students aged 15-18 years in metropolitan Melbourne, Australia. The 99 male and 145 female participants were recruited for the longitudinal study in 1994-95 from 4 secondary schools in the city. 81% reported using a condom during their most recent sexual encounter, with 93% of the men and 70% of the women reporting condom use, a significant difference. The young women, however, were more knowledgeable about STDs than were the young men. 61% of both sexes reported discussing condom use with their most recent sex partner. Age was the only variable associated with young men's condom use, although there was no clear pattern of association. For young women, the probability of condom use was positively associated with discussion about condom use, and negatively associated with partner's increasing age and use of other contraceptives. Condom use was not related to reported alcohol or drug use on the part of the respondent or their partner, levels of knowledge about sexually transmitted diseases, or type of relationship.