Over a thirteen year period forty patients underwent surgery to remove an orbital dermoid cyst. Cysts which became manifest after the age of three years were deeper and larger than most that were noted before that age. Three out of four epidermoid cysts appeared after the age of 17 years and had an intracranial component. The majority of cysts showed histological evidence of leakage and associated inflammation. It is our view that dermoid cysts should be totally excised because they gradually enlarge and cause inflammation and scarring in adjacent structures.