Thin cell layers approximately 1 × 8 mm in size were excised from secondary embryoids of Brassica napus ssp. oieifera cv. Primor. Further secondary embryogenesis was observed in about 35% of the thin cell layers cultured on a medium without the addition of plant growth regulators. In one experiment using 168 thin cell layers, the explants showing embryogenesis produced an average of 23 embryoids per explant. Secondary embryogenesis was found to be inhibited with the addition of high concentrations of auxin or cytokinin to the culture medium. Callus, root, shoot, and leafy structures were obtained depending on the type and concentration of auxin and cytokinin used. The embryoids from thin cell layers were capable of producing further secondary embryoids.