This paper describes the delayed eruption of permanent first molars, which included 56 cases in the maxilla,19 cases in the mandible and 1 case in the maxillary and mandibular first molar. Based on radiographic examination, the cause of the disturbed eruption in most of cases of the maxilla could not be clarified. The radiographic findings of arrested eruption in most of the cases of the mandible showed an enlarged follicular space and radiopaque masses around the teeth. Ectopic eruption was present in 13 cases of the maxilla and in 5 cases of the mandible. When we found pathological entities and abnormal position of the teeth, we performed surgical removal of the impediment or exposure of the crown. After the surgery, if there was no tendency to erupt, we opted for a second exposure or traction, and it that point most of the cases had the eruption process successfully completed. When there were no pathological entities or ectopic position of the tooth, we examined the tooth development based on their panoramic radiographs. Most of the cases revealed delayed development of the first molar in conjunction with an adjacent second molar. After periodic observation, we found that they had erupted spontaneously at ages 8 to 11, and this fact made us believe that we should keep these cases under observation without any intervention on our part.