Background:Intradiploic epidermoid cysts (IEC) are rare, benign lesions derived from ectodermal remnants during neural tube closure. Their origin is still debated or unknown.Objective:Analyzing of the patients with intradiploic epidermoid cysts operated in the authors' department.Methods:The patients with IEC who were operated in the authors' department between January 2014 and December 2015 were investigated from data file.Results:Six patients with IEC were found, reviewed the literature, and noted that these cysts usually occur in adults. There are only 3 young cases that occurred after head injury.Conclusion:It was shown that the nontraumatic IEC are more frequent in older ages. In youngs, it can generally be embryologic or rarely of mechanical origin following trauma. Cranial trauma may be important for developing of IEC. Trauma may lead to inclusion of epidermal cells into the diploe of the skull and may be a reason of intradiploic epidermoid cyst in older age. The effect of older age, and gender difference on occurrence should be investigated.