Abstract Copolymers of propylene/1‐octene and propylene/1‐hexene were synthesized in slurry phase polymerization using MgCl 2 /TiCl 4 /Diester based catalyst system. The Al/Do (co‐catalyst/external donor), Al/Ti (co‐catalyst/catalyst) mole ratio variations were investigated for effect on polymerization and copolymer properties. Incorporation of comonomer (1‐hexene and 1‐octene) has influenced the molecular weight distribution (MWD) of resultant copolymers as well as isotacticity. The differential Scanning Calorimetry (DSC) results showed lower melting point for propylene/1‐hexene than propylene/1‐octene copolymer. The gel permeation chromatography (GPC) study indicated broad MWD of both type of copolymers compared to homo PP. The 13 C NMR has also been performed to quantitatively evaluate incorporation of comonomer in polymer backbone. Propylene copolymerizaiton with hexene resulted in the copolymer which have relatively higher amount of 1‐hexene compared to 1‐octene incorporation in copolymer of propylene/1‐octene with similar catalyst system explain the reason for lower peak melting points.