The effects of medium replacement on the development of embryos from the globular to torpedo-shaped stage were investigated in carrot suspension cultures. Partial replacement of the medium was more effective than total or non-replacement at a high embryo density. The frequency of somatic embryogenesis (embryo development from globular to torpedo-shaped) at a high embryo density (500 globular embryos/ml) was increased to 53.1 % by partial replacement of the medium as compared to 36.8% without medium replacement. Partial replacement of the medium is a simple method that should prove useful for the mass production of somatic embryos.