Objective. To describe the characteristics of Mexican children and adolescents 5-17 years with severe functioning difficulties and disability and explore their participation in child labor. Materials and methods. Using data from the National Survey of Boys, Girls and Women in Mexico 2015 we estimated prevalence of functioning difficulties and disability and used logistic regression to explore the association between this condition and child labor. Results. While 11.2% of Mexicans 5-17 years-old has severe functioning difficulties or disability, 13.4% work. The functioning difficulty and disability domains with the highest prevalence are experiencing anxiety (5.4%) and depression (1.5%) daily. Children and adolescents with severe functioning difficulties and disability are 70% more likely to do child labor [OR=1.7, 95%CI:1.2,2.4]. Educational lag doubles the likelihood of doing child labor [OR=2.2, 95%CI:1.5,3.3]. Conclusions. Guaranteeing educational opportunities and respect for the rights of children with severe functioning difficulties and disability is essential to achieve development of their full potential.