Graft copolymers of propene with styrene were analyzed with regard to their chemical heterogeneity using both SEC coupled to FT‐IR spectroscopy and CRYSTAF. The SEC‐FTIR indicates chemical homogeneity of the copolymer samples. The decrease in crystallization temperature in CRYSTAF does not correlate with the concentration of PS in the samples but it correlates decisively with the branching frequency. The length of the PS branches does not influence the crystallization temperature in CRYSTAF, although the longest branches in the individual samples were 44 times longer than the shortest ones.