The present article gives a comparison of the peel behaviour of the adhesive peel system ethylene vinyl acetate copolymer/polyethylene (EVA/PE) and the cohesive peel system low-density polyethylene/isotactic polybutene-1 (LDPE/iPB-1) using the fracture mechanics values energy release rate G Ic and adhesive energy release rate G aIc. The influence of the content of the peel component and the influence of the peel angle on the peel behaviour was investigated. In case of the adhesive peel system, an independence of the adhesive energy release rate on the peel angle was found. In case of the cohesive peel system, two zones of G aIc could be identified, (1) G aIc is independent of the peel angle and (2) G aIc depends linearly on the peel angle. This difference in G aIc could be strongly addressed to the type of crack propagation. In general the results revealed that fracture mechanics values like G Ic and G aIc can be used to get further and deeper structure-sensitive information of the investigated material system.