Street children are among the most marginalized children, globally, who experience severe violations of their rights and face multiple deprivations. This study aimed to describe street children’s characteristics and working conditions in Iran. Method: This cross-sectional rapid survey was conducted from March to May 2017 in six major cities in Iran. The sample group consisted of Iranian and non-Iranian girls and boys, aged 10 to 18, who worked on the streets for at least one month prior to the survey. Time–location based sampling was used. A total of 856 Children were randomly selected from 464 venues, including corners of streets, parks, metro gates, bus stations, shopping malls, and shopping centers frequented by street children. Results: Findings showed that 90% of participants were boys, 60% were between 10 and 14 years old, almost 50% attended school, 12% were illiterate, and 32% had quit school. Children of Afghan nationality comprised 54% of the study participants, and the rest were Iranian. Of all participants, 85% resided with family or relatives. Most children (75.5%) worked more than 5 h daily, and vending (71.2%) and waste picking (16.1%) were common activities. Street children suffered, mainly, from harsh weather (22.7%), insults and beatings of everyday people (21%), starvation (20.7%), and police repression (15.4%). More than half of the study participants were not involved in intervention programs, and just 7% of them had attended any health education programs. Conclusion: Street children reported little to no service use, which may contribute to poor health. Street children require immediate attention to improve their wellbeing. Decision-makers and academicians should collaborate on intervention development research to design appropriate health and social interventions targeted at street children.