I-cell disease (mucolipidosis II) is a rare hereditary disorder of lysosomal storage disease, with its primary defect the deficiency of an enzyme responsible for lysosomal enzyme processing, resulting in multiple lysosomal enzyme insufficiency. We report on the clinical, radiological and biochemical features of mucolipidosis II in one case. A 2.5-year-old male infant was found to have developmental delay, coarsening of facial appearance, braciocephali, craniosynositosis, protruding eyes, gingival hypertrophy, impaired enamel formation, kyphoscoliosis, umblical and inguinal hernias and right-hand focomelia. Radiologically the infant showed changes that are characteristic for mucolipidosis II. Lysosomal enzyme tests (including alpha-mannosidase, B-hexosaminidase) were 100–400-fold higher than normal in plasma. Both the clinical and radiological and gross elevation of plasma hydrolates was typical of mucolipidosis II (I-cell diseases).