SUMMARYFive cases of tumours of the pineal region have been descnied. They indude a pineocytoma (Case One) and a teratoma (Case. Two). A tumour arising from the cerebellar vermis illustrates one of the problems in diagnosis of pineal neoplasms.The classic deformity of the posterior third ventricle is illustrated on pathological examination and ventriculography. Other radiological appearances on plain films, angiography, pneumoencephalography and C.T. scan have been discussed and the literature reviewed.