The objective of this study was to find out the street-based adolescents’ self-perceptions of risk from HIV infection and their condom use practices. This cross-sectional descriptive survey was conducted in four designated street-based adolescents’ rehabilitation centres under the Nairobi City Council in Kenya. Structured questionnaires were used to collect quantitative data, which were analysed quantitatively and reported descriptively. A total sample of 150 street-based adolescents aged between 12 and 25 were surveyed in a multistage sampling procedure. Of all the respondents (55.3% male; 44.7% female), majority 92%(138) had had sexual intercourse, of whom only 13.%(20) used condoms at first sexual contact. Some 52%(79) considered themselves to be at medium to low risk of HIV infection. On condom with commercial sex partners, it was found that 20.0%(30) did not use condoms. When asked to indicate who suggested condom use (for those who used them), 8.7%(13) indicated that they themselves suggested condom use while the other 2.7(4) negotiated with the partner. On frequency of condom use, 7.3%(11), 3.3%(5), 9.3%(14) indicated that they used them every time, almost every time, and sometimes respectively. The greater majority comprising 76.7%(118) indicated that they did not use any condoms. The survey revealed that the major obstacles to condom use among street-based adolescents were thus; partner objection, not liking condoms, shame, and belated thinking about condoms. Concerning knowledge of places to get condoms 5.3 %(8) and 30.7%(46) indicated that they did not know where to get male and female condoms respectively while 12%(18) indicated that they never heard of female condoms. This is a call to all stakeholders to ensure supply of and access to condoms, coupled with public education and advocacy to increase condom use among street-based adolescents.