We report the case of a 6-year-old boy with a nasopalatine duct cyst. He consulted a dental clinicbecause of median diastema in the upper medial incisors. Radiographic examinations revealed a radiolucent areain the maxilla, extending from the nasal floor to the alveolar ridge between the medial incisors, which inclinedmedially. The upper lateral incisors were still impacted far from the normal position. We performed marsupializationto prevent damaging the incisor pulp. After that the lateral incisors erupted and malalignment of both incisorsimproved; however, the cystic cavity did not disappear completely. Extirpation of the remaining cyst followed bywound closure was performed at a secondary operation 9 months later. This case was considered to be rarebecause it occurred in childhood and affected the dental alignment at the time of teeth eruption.