Subsequent crystallization behavior during cooling for two random propylene-ethylene copolymers with 6 mol % ethylene co-units but different molecular weights initially in a pure alpha-form or pure gamma-form processed at different melt temperatures was investigated using differential scanning calorimetry and wide-angle X-ray diffraction techniques. The onset crystallization temperature (T-onset) and fraction of the two polymorphs after crystallization depended on the molecular weight, initial polymorph, and melt temperature (T-melt). At high T-melt (120-160 degrees C), T-onset and the fraction of the gamma-form (f(gamma)) increased with decreasing T-melt. For the high molecular weight sample initially in a-form, a higher T-onset and f(gamma) than the one in the gamma-form was observed because a higher T-melt was needed to fully homogenize the melt for samples initially in the alpha-form due to the different morphology between the samples of different polymorphs. For the low molecular weight sample, the initial polymorph did not affect this process.