A procedure is described for the isolation of large numbers of viable aleurone protoplasts. After treatment with "Onozuka" cellulase protoplasts were obtained which were surrounded by a thin, "Onozuka"-resistant wall. These cells were termed "spheroplasts". Treatment of spheroplasts with "Glusulase" digested away the residual wall, yielding naked protoplasts. Measurements of respiration using a Clarke-type oxygen electrode indicated that aleurone cells isolated by this procedure were viable.