The processing behaviour of various EPDM/EPM rubbers and compounds was studied with the help of technological testing methods. A qualitative agreement could be established particularly between the DEFO test and the Mooney-Relaxation test with Fourier analysis (FT). Analysis of the molecular mass distribution with GPC (gel permeation chromatography) showed the polydispersity to be reflected in the elastic properties. The mechanical loss factor of the raw polymer was found to decrease with increasing polydispersity. Due to the increase in parts of high molecular mass, clearly recognizable in part by a bimodal molecular mass distribution, the degree of branching presumably rose, with an increase in the elasticity of the polymers studied. The different elastic behaviour of the raw polymers has a direct influence on the viscosity of the compound.