Poly(ethylene-co-propylene) macromonomer (EPM) was synthesized in a high-temperature continuous stirred tank reactor (CSTR) with [C5Me4(Si-(Me2NBu)-Bu-t)]TiMe2 (CGC-Ti) as the catalyst system. PE samples with EPM long chain branching (LCB) were produced by semi-batch copolymerization of ethylene and EPM with CGC-Ti. The LCB frequencies were up to 21.8 EPM side chains per PE backbone. The effects of temperature and ethylene pressure on the degree of EPM grafting and catalyst activity were examined.