The influence of intrachain double bonds on the melt crystallization kinetics of some linear polymers such as polyethylene, aliphatic polyesters, and polyamides is discussed. The analysis of the experimental results carried out in terms of the kinetic crystallization theory agrees, for all the polymers investigated, with a growth process of spherulites controlled by a surface two-dimensional coherent secondary nucleation. The presence oftransdouble bonds along the chain of the polymer affects the values of some kinetic and thermodynamic parameters related to the process of melting and crystallization. The dependence of Δ Φ* and σeon the percentage of unsaturation shows different trends for the condensation copolymers and for ethylene-butadiene copolymers. This behavior is interpreted in term of both different molecular and crystallographic structures of the copolymers.