Dentinogenesis imperfecta is an autosomal dominant disorder of tooth development characterized by the presence of opalescent dentine, resulting in a dusky blue to brownish discoloration of the teeth. It is the most common dental genetic disease. This condition is genetically and clinically heterogeneous, it may affect only the teeth or it may be associated with the osteogenesis imperfecta. Diagnosis is based on history, clinical examination and radiographic features. This report describes an 18 year old male patient who showed the characteristic dental features of dentinogenesis imperfecta.