Abstract Introduction: Rare health conditions as mucopolysaccharidoses (MPS) can directly influence functioning experiences. Mobility restriction, osteoarticular alterations, leads to delayed neuropsychomotor development are some of the negative impacts of MPS. Aims: The purpose of this study is to evaluate the functioning of children with MPS, from the International Classification of Functioning, Disability, and Health (ICF) perspective. Methodology: It is a case series study with a sample of 15 children and adolescents with MPS with a median age of 12 years, followed in a tertiary hospital in Rio de Janeiro, Brazil. Results: The patients were assessed by the model ICF and results were as following: regarding body functions, most categories presented slight impairment. For mobility of joints and gait, the impairment was severe. Activity and participation with most significant limitations were "learning to read/write", "read/write", "listening" and "performing multiple tasks." In self-care, the main limitations were in "drinking", "taking care of body parts" and "taking care of one's health." Also, there were restrictions on "doing household tasks", "basic economic transactions", "community living" and "religion and spirituality". Conclusion: MPS can have a significant impact in different body systems which act as limiting activities that require body mobility.