The molecular weight (M) dependence of the linear crystal growth rate (G) and the influence of the super-cooling on the relationship between M and G were studied. The molecular weight dependence of G has been expressed generally as G proportional to M-alpha at a given super-cooling. The temperature dependence of G shows a bell shape with the maximum growth rate (G(max)). The value of alpha was -0.5 at the temperature (T-cmax) of G(max). However, the small super-cooling and the small molecular weight gave a large negative value of alpha. In other words, the value of alpha was dependent not only on the degree of super-cooling (AT) but also on the molecular weight. The effect on alpha by these two factors (Delta T and M) goes off to zero at T-cmax and alpha yields to -0.5. G(max) can be defined as a characteristic intrinsic value to the crystal growth behavior. The molecular weight dependence of G(max) was scaled and expressed as a -0.5 power to molecular weight for all crystalline polymers. (c) 2005 Elsevier Ltd. All rights reserved.