Purpose: To validate the major bony causes and postoperative results of the first metatarsal head plantar pain. Materials and Methods: We experienced one case of the fracture and non-union of the medial sesamoid treated by autogenous calcaneal bone graft, one case of the fracture and non-union and two cases of the hypoplasia of the medial sesamoid treated by excision of medial sesamoid, one case of the arthrosis between the first metatarsal head and the medial sesamoid treated by plantar 1/2 partial excision of the medial sesamoid, and two cases of the metatarsus primus nexus treated by basal metatarsal closing wedge osteotomy between October 1995 and September 1999. The mean follow-up period was 28 months. We evaluated the results by using of the clinical rating systems for the hallux and the radiographic findings. Results: An excellent results were achieved in all cases except one which was preoperatively diagnosed as metatarsus primus nexus. But, clinically this one case also satisfied with the postoperative result. Radiologically, We did not find the malunion or nonunion of the medial sesamoid treated by bone graft and of the metatarsus primus flex us treated by basal metatarsal closing wedge osteotomy. And also we did not find the postoperative fracture of the medial sesamoid treated by plantar 1/2 partial excision. There were no postoperative complications in all cases. Conclusion: We think that the good results may be achieved from the patients with the plantar pain of the first metatarsal head by the exact diagnosis and aggressive treatments.