Child labor is one of the important social issues that deprive children of many fundamental rights, and make them face many problems and consequences, including health problems. Thus, this study was conducted with the aim of examining the health of working children in Tehran. This is an ethnographic study that was conducted using Carspecken’s approach and was completed in 2022. The main participants of this study included working children aged 10–18 years living in Tehran. In order to collect information, the researcher was present at the workplace, school, and living places of working children for more than two years, observing their lives and activities. Formal and informal interviews were also conducted with the working children and informed people. In total, hundreds of working children were assessed and observed in this research. A friendly conversation was formed between the researcher and more than 50 children, and official interviews were conducted with six of the working children. Also, more than 10 official interviews were conducted with informed people and parents of working children. In addition to observations and interviews, documents such as medical records and drawings of working children were also examined and interpreted. The information obtained from observations, interviews, and documents was entered into MAXQDA software, and its raw codes were extracted. The high-level codes as well as sub and main categories were formed from the aggregation of low-level codes. Impaired health was formed from three subcategories of tormented body (work and environmental trauma, sexual abuse, malnutrition, fatigue, sleep disorder and inadequate hygiene), disquieted mind (anxious children, depression and isolation, reduced self-esteem and unfocused mind) and disrupted sociability (negative social role modeling, aggression and violence, stubbornness and vindictiveness, harassment and nuisance, reprehensible social behaviors, neglecting others’ ownership, disturbed relationships and out-group self-censorship). The results of the present study showed that the health of working children is compromised in various physical, psychological, and social ways. Therefore, some measures should be taken at the national and international levels to improve their health, such as revising the existing laws regarding children and informing children of their rights.