OMD (osteosclerotic metaphyseal dysplasia) is a very rare sclerosing bone disorder, first described by G. Nishimura in two Japanese siblings in 1993 (6). We report the case of a 12-month-old male with hypotonia, developmental delay and sclerosis of the metaphyses and epiphyses of specific bones. This 36-week gestation boy was born to a 26 year old gravida 5 para 1 Turkish mother and a 27 year old nonconsanguineous father. Radiographic findings obtained during the hospital stay included bilateral symmetrical osteosclerosis of the metaphyseal portions of the long bones in the upper and lower extremities with osteopenic shafts. Narrow bands of metaphyseal osteosclerosis were detected in the short tubular bones of the hands and feet. Growing parts of bilateral scapula, iliac, pubic and ischial bones show sclerotic bands. In addition superior and inferior plates of vertebras, transverse processes of sacral vertebras, all visible epiphyses, carpal and tarsal bones also show sclerotic changes. The scalp was unaffected. Based on the clinical, radiographic, and laboratory findings, a diagnosis of OMD was made. We do not know any of the osteosclerotic bone disorder with changes including hypotonia, mental and motor developmental delay and metaphyseal sclerosis of the bones with a unique distribution except OMD. The syndrome is characterized by developmental delay of a progressive nature, hypotonia, elevated alkaline phosphatase, and late-onset spastic paraplegia 18 years ago. Our patient is the 4th case of OMD described in the literature share some clinical and radiological similarities with other three reported cases of osteosclerotic metaphyseal dysplasias.