The crystallization behaviour of ethylene-vinyl alcohol copolymer/nylon-6 blends was studied by isothermal and nonisothermal crystallization. In case of miscible blends of nylon-6 with ethylene-vinyl alcohol copolymers composed of 71, 62 mol% vinyl alcohol, the crystallization rate of nylon-6 is decreased by added copolymer, and this decrease is caused by the decrease of T_m and dilution effect of tile added copolymer. But, in case of immiscible or partially miscible blends of nylon-6 with polyethylene or ethylene-vinyl alcohol copolymer composed of 18 mol% vinyl alcohol, the crystallization rate of nylon-6 is not so much decreased or rather increased, and these results are caused by tole nucleating effect of copolymer or polyethylene. The crystallization rate of ethylene-vinyl alcohol copolymers composed of 71, 62 mol% vinyl alcohol is increased by added nylon-6 and this is caused by the decrease of T_g and the nucleating effect of nylon-6.