Objectives: report a case of unusual regional odontodysplasia affecting all posterior maxillary and mandibular quadrents in a 30 years old Libyan male patient. Method Methods: Diagnosis was done by clinical examination, OPG radiograph, Intra oral preapical radiograph and histopathological examination of gingival hyperplasia Results: diagnosis was confirmed as regional odontodysplasia in 30 years old Libyan patient. Conclusions: regional odontodysplasia is a rare condition that is diagnosed up on clinical, radiographical, and histopathological finding. In our case the finding was observed in posterior teeth of four quadrants with normal anterior segment. The patient exhibit several common clinical features that strongly suggest diagnosis of Regional Odontodysplasia.