Mucopolysaccharidosis I (MPS I) is a rare inherited disorder characterized by physical deformities and developmental anomalies. Part of a group of clinically progressive disorders, it is caused by the deficiency of the lysosomal enzyme, α-L -iduronidase, which results in intralysosomal accumulation of dermatan sulfate and heparan sulfate and in turn causes cell dysfunction. Two sisters, one 11 years old and the other 7, both MPS type I H/S, came to our diagnostic center. Hand-wrist radiographs revealed bullet-shaped phalanges with proximal pointing of the second to fifth metacarpals. Ultrasonographic examination showed splenomegaly in the younger child. Radiography of the pelvis showed a narrow pelvis with flared iliac wings. A skull skiagram showed J-shaped sella.