The Maroteaux-Lamy disease, or mucopolysaccharidosis type VI is an inherited metabolic disorder severe and rare. It is caused by a deficiency of the enzyme arylsulfatase B. It is characterized by a heterogeneous clinical, radiological and genetic. We report the case of a Maroteaux-Lamy syndrome of in a child aged 7 years whose diagnosis was suspected clinically by the combination of a dysmorphic syndrome, a failure to thrive not harmonious, hepatomegaly and normal intelligence. Radiological exams have objectified dysostosis multiplex. Biochemical analysis of urine showed the abnormal presence of dermatan sulfate. The determination of leukocyte enzyme activity confirmed the diagnosis by showing arylsulfatase B deficiency. Hence the diagnosis of syndrome Maroteaux-Lamy in its mild form (type B) was selected.