The study was performed to determine the ultrastructural characteristics of central neurocytoma and its features in primary cell culture. Fresh tissue from three tumors was mechanically and enzymatically dissociated into individual cells, which were cultured onto poly-L-lysine precoated Aclar coverslips in the media. The tumor cells attached to the surface of the coverslips within 12 to 24 h and delicate cytoplasmic processes developed within 2 to 3 days. Electron microscopic examination of the cultured tumor cells and the tumor tissue supported neuronal origin. Combined tissue culture and electron microscopic study provides a rapid, reliable, and reproducible means for the diagnosis of central neurocytoma.