Background and Aim: Mucopolysaccharidosis type I (MPS I) is a rare and highly progressive autosomal recessive, genetically-metabolic disorder that results of the mutation in the gene responsible for the production of Alpha-L-Iduronidase enzyme, which ultimately leads to destruction and cell death of tissues. The patient is asymptomatic at the time of birth, but few months after birth, symptoms gradually appear in the person's phenotype. Respiratory, skeletal, neurological, cardiac, gastrointestinal and ocular disorders are obvious in these patients. The purpose of this study is reporting a case of MPS I.Patient introduction: The patient is a 7 years old boy, repeatedly admitted to the Heshmatieh Hospital of Sabzevar University of Medical Sciences, due to a weak immune system, high fever, and complications of his MPS genetic disease. At 2.5 years old, MPS had been definitively diagnosed.Conclusion: In this patient, almost all symptoms of the Hurler syndrome including third tonsil, hepatomegaly, splenomegaly, large skull, large tongue, ocular corneal opacity, and the presence of yellow spots in sclera, spinal deviation, Umbilical hernia, hearing loss and the stenosis of the mitral valve were seen. Unfortunately, due to the lack of definitive treatment, only 20% of the patients have a chance of survival and recovery. MPS usually leads in death before the age of 20.