Intraventricular neurocytomas are rare or have been earlier misdiagnosed as Oligodendroglioma, a tumour which they closely resemble at light microscopy. Three such intraventricular tumours are described, all of which were diagnosed as Oligodendroglioma on CT scan and at routine light microscopy. The judicious use of EM for a definite diagnosis of these tumours is emphasised. Cells with multiple processes, abundant RER and dense core vesicles and profiles of axon terminals with groups of synaptic vesicles, clinches the diagnosis. Even though the prognosis of neurocytomas is generally believed to be good, it may depend on whether they have only neuronal or associated Glial differentiation.