BackgroundVoluntary medical male circumcision (VMMC) is a critical component of HIV prevention. VMMC policies have achieved initial targets in adult men yet continue to fall short in reaching younger men and adolescents.SettingWe present the cost and scale-up implications of an education-based, VMMC intervention for adolescent street-connected males, for whom the street has become their home and/or source of livelihood. The intervention was piloted as part of the Engaging Street Youth in HIV Interventions Project in Eldoret, Kenya.MethodsWe used a micro-costing approach to estimate the average cost of a VMMC intervention in 116 street-connected youth. Average cost was estimated per individual and per cohort by dividing total cost per intervention by number of clients accessing the intervention over a 30-day period. Total average costs included direct and support procedure costs, educational costs, and direct research costs. Cost-effectiveness was measured in cost per DALYs averted over a 5 and 10-year period.ResultsThe total cost of the intervention was $12,526 over the 30-day period, with an average cost per individual of $108. The direct VMMC procedure cost was approximately $9 per individual. Personnel costs contributed the greatest percentage to the total intervention cost (38.2%), with mentors and social workers representing the highest wage earners. Retreat-related and education costs contributed 51% and 13% respectively to the total average cost, with surgical equipment costs contributing less than 1%. At a cost of $108 per individual, the intervention averted 60166 DALYs in 5 years resulting in a cost per DALY averted of $267.ConclusionThe VMMC intervention was highly cost-effective in Kenya, despite the additional costs incurred to reach SCY. Further scale-up may be warranted to effectively apply this intervention in comparable populations.Electronic supplementary materialThe online version of this article (10.1186/s12981-018-0207-x) contains supplementary material, which is available to authorized users.