Abstract: Field experiments in 1970–1975 showed that application of 0.75–1.00% of sodium ethylxanthate at the late milk-ripe stage by a foliar spray increased the water loss from the grain and hastened the yellow-ripe processes without any significant effect on the grain-filling processes of the cereals. The treatment caused an earliness in spring wheat, winter wheat, barley and rye for 5–7 days. The 1000-grain weight was decreased by 5% or was increased slightly depending on the locality and the cultivar used. There was no adverse effect on grain characters and its germination capacity by the treatment of sodium ethylxanthate. The crude protein content of the grain was slightly increased whereas the starch content was decreased by the treatment. It was considered that the accelerated less of water from the grain and rapid accumulation of dry matter in the grain may be responsible for the earlier maturity of cereals by the trestment of sodium ethyLxanthate. Effects of sodium ethylxanthate treastment on the translocation and accumulation of materials in cereal grain during maturation were studied with 144CO2 as a tracer. The results showed that under the influence of sodium ethylxanthate, the mobile sugars were increased in stems and leaves, and the translocation of assimilates to the grains as well as the accumulation of dry matter in the grain were not affected.