Bone flaps are occasionally not replaced because of brain swelling or for other reasons. Various methods for preserving the free bone flaps have been described. Reimplantation of a free bone flap after a period of preservation outside the body, however, may be complicated by infection, and facilities for proper preservation under sterile conditions may not be available. We present a new technique for preserving the bone flap under the scalp until brain swelling has resolved. The bone flap is reimplanted 12-48 days later. No serious complications related to this technique have been encountered in the 37 patients in which it was used.