Pycnodysostosis (OMIM 265800) is an uncommon hereditary disorder characterized by osteosclerosis of the skeleton, short stature, and bone fragility. The syndrome was first described by Maroteaux and Lamy (1962). Facial dysmorphology, hypoplasia of the mandible,dysplasia of the skull, bones with delayed closure of the cranial sutures, clavicular dysplasia, acroosteolysis or partial aplasia of the terminal phalanges, and abnormal tooth eruption have also been reported (Gelb et al., 1995). An autosomal recessive mode of inheritance has been also suggested and the locus of the disease was initially mapped to human chromosome 1q21 by genetic linkage (Bernard et al., 1980). Since then, several mutations on unrelated patients and consanguineous families have been identified in the cathepsin K gene (CTSK), affecting osteoclast function.Only two previous reports have demonstrated the presence of craniosynostosis in patients with pycnodysostosis(Fleming et al., 2007; Osimani et al., 2010). The purpose of this case report is to describe the craniofacial and dental features of a 12-year-old boy with pycnodysostosisand an uncommon association with craniosynosotosis.