Introduction The study aimed to identify the factors associated with condom use during the last sexual intercourse.

Methods A population-based survey with youths aged 15–24, in São Paulo. The participants answered a questionnaire including knowledge and sexual behavioural data.

Results for 821 men and women the condom use during the last sexual intercourse was associated with: never having been married [adjusted prevalence ratio (PR_adj): 1.54 among men; 1.26 among women], having used a condom in the sexual onset (PR_adj:1.23 among men; 1.54 among women), receiving condoms free of charge (PR_adj:1.39 among men; 1.37 among women); besides, among men: casual sexual partner in the previous year (PR_adj:1.24) and same-sex sexual partner (PR_adj:1.23); among women with the sexual onset after 15yo (PR_adj:1.25). HIV-testing has displayed a negative association for women (PR_adj: 0.72).

Conclusion The condom is widely known, there is a pattern of it use during the first and last sexual intercourse; free condoms are important to improve it use by the youths, and people use condom as a risk management strategy. Condom as prevention strategy is still useful. After these results, the strategy of prevention was adopted as a public policy in the city of Sao Paulo: large condom dispensers were allocated in the 28 urban bus terminals, where 6 million people pass around daily and by the end of 2016, 80 million free condoms will be distributed.