An improved method for the electron microscopic study of sectioned tissue cultures of human brain tumors is based on commercial perforated cellophane sheets upon which the cells are grown. Specimens are fixed with buffered osmium tetroxide, imbedded horizontally in Metacrylate or Vestopal without separating them from the cellophane sheet and the monolayer cut in sections of 500 A. Electron micrographs show a very good preservation of intracellular and intercellular structures.