Authors performed in 1979 through 1991 in the Orthopaedic Department of the Semmelweis University of Medicine 47 osteotomies on the base of the first metatarsal bone in 37 patients. After the operation the intermetatarsal angle was in average under 10 and the metatarsophalangeal angle under 20 degrees. In chosen cases and with careful surgical technique good result can be obtained from the osteotomy of the base of the first metatarsal bone. The technique is not complicated, the osteotomy is healed quickly and well and the internal fixation makes early mobilization possible. It can and should be carried out in cases in which the intermetatarsal angle exceeds 10 degrees. After its performance, if necessary, operation beside the metatarsophalangeal joint may also be carried out.