The nonisothermal crystallization behavior of one metallocene-based isotactic polypropylene and three propylene-decene-1 copolymers was studied. The effects of comonomer content and cooling rate were investigated. It was found that comonomer units enchained systematically reduce the crystallization temperature (T-c), melting temperature (T-m), fusion enthalpy (DeltaH(f)), and crystallinity (X-c). Such an effect becomes more evident at a faster cooling rate. With increasing comonomer content, the supercooling required for crystallization increases and the overall crystallization rate is reduced. The Avrami equation is applicable to describe the nonisothermal crystallization kinetics of propylene-decene-1 copolymer. It was shown that, although the reduced crystallization rate constant Z(c) increases with comonomer content, the Avrami exponent decreases with comonomer content and cooling rate, leading to the smaller overall crystallization rate and larger crystallization half-time of the copolymer with higher comonomer content. (C) 2004 Wiley Periodicals, Inc.