Trauma to the primary incisors may cause developmental or eruptional disturbance of the permanent successors. Two cases illustrate developmental disturbances of arrested root formation, dilaceration, and eruptional disturbances of impaction, ectopic eruption of permanent successors caused by traumatic injury to deciduous incisors. The patient of the first case suffered trauma at the age of 4 years 7 months, causing alveolar bone fracture including the maxillary right primary central and lateral incisors that were immedi-ately extracted. The second patient had trauma episodes at the age of 3 years. Avulsion of the maxillary primary right central and lateral incisors were occurred due to trauma. After such trauma, regular follow-up including radiographs is necessary to detect early any possible interference with normal eruption of permanent successors.