Thirteen cases of open depressed fractures of the skull in which methyl-methacrylate was primarily used are reported. The site of the depressed fractures was frontal in 9 cases, parietal in two, parieto-temporal in one and parieto-occipital in one. In 5 cases, only the bone was injured; in three cases dura mater was damaged; in 5 cases brain and dura mater were damaged. In 5 cases, only a cranioplasty was performed and in 8 cases a dura mater graft was associated. The follow-up was from two months to two years without any complication as infection or rejection of the methylmethacrylate.