Four cases of cerebral dermoid tumour with an intraventricular, occipital and sellar location are reported, representing 0.04% of the verified cerebral tumours in the authors' statistics. A recurrence occurred after one year in the first case of intraventricular dermoid tumour; after the second operation aseptic meningitis developed and the patient died. In the second case microscopic examination revealed aspects of malignant transformation of the tumour. The symptoms did not differ from those of other cerebral tumours. Operations should be radical whenever possible, avoiding dispersion of the tumour contents in order to prevent a recurrence or aseptic meningitis.