To evaluate the effect of fusion of the first metatarsophalangeal joint on the first intermetatarsal angle, a series of 62 consecutive first metatarsophalangeal fusions was reviewed. Of these, 47 had sufficient data to be included in this study. The results of this study showed that the change in the first intermetatarsal angle following a first metatarsophalangeal joint arthrodesis is directly proportional to the preoperative first intermetatarsal angle. Therefore, when a first metatarsophalangeal joint arthrodesis is performed on a patient with a wide intermetatarsal angle, a concomitant proximal first metatarsal osteotomy is usually not indicated.