Every craniotomy requires immediate replacement of a fresh autograft of skull or, in the presence of cerebral swelling, delayed cranioplasty. The use of artificial implant materials for cranioplasty has been reported by many authors. Among them, acrylic resin and titanium are most commonly used in neurosurgical practice; however, untoward complications such as infection and fluid collection appear at times. In cases with a large bone defect we have been using autogenous bone flaps, which was removed during the initial surgery, then preserved at -70degreesC. Twenty cases of cranioplasty with autogenous bone grafts stored in a deep-freezer are reviewed. Skull sections removed aseptically at initial craniotomy were frozen and stored for 18 to 320 days(average 102 days) at -70degreesC. At cranioplasty the pericranium was completely removed, and the skull plate was immersed in antibiotic solution for one hour in room temperature and fixed in skull defect site. The changes of replaced bone flaps were studied by follow-up skull roentgenograms and radionuclide scintigraphy. The results of follow-up for an average period of 14 months were satisfactory from the standpoint of brain protection and cosmetic reconstruction. Delayed resorption of grafted bone was observed in two cases. No serious complications were seen except in two cases, whose bone flaps had to be removed due to an epidural abscess. These results suggest that autogenous skull cranioplasty using deep freezing skull plate offers several advantages: 1) the reconstruction contour is nearly same as preoperative feature: 2) operation time is much shorter than other methods: 3) early cranioplasty is possible as soon as patient's condition allows general anesthesia: 4) cost effective.