Objectives This study presents findings from piloting an adapted evidence-based intervention, Stepping Stones and Creating Futures, to change street-connected young people's HIV knowledge, condom-use self-efficacy, and sexual practices. Methods Eighty street-connected young people participated in a pre-and post-test mixed methods design in Eldoret, Kenya. The primary outcome of interest was HIV knowledge. Secondary outcomes included condom-use self-efficacy and sexual practices. Multiple linear regression models for change scores with adjustment for socio-demographic variables were fitted. Qualitative and quantitative findings are presented together, where integration confirms, expands on, or uncovers discordant findings. Results Participants had a significant increase in HIV knowledge from pre-to post-intervention. The median HIV knowledge score pre-intervention was 11 (IQR 8-13) and post-intervention 14 (IQR 12-16). Attendance was significantly associated with HIV knowledge change scores. Qualitatively participants reported increased HIV and condom-use knowledge and improved condom-use self-efficacy and health-seeking practices. Conclusions Our findings support the potential for further testing with a rigorous study design to investigate how best to tailor the intervention, particularly by gender, and increase the overall effectiveness of the program. Keywords HIV Á Condom use Á Evidence-based intervention Á Street youth Á Kenya Á Eldoret Á Sexual practices This article is part of the special issue ''Sexual and reproductive health of young people-Focus Africa''. The Rudolf Geigy Foundation (Basel, Switzerland) funded the open access publication of this article.