During thermoplastic processing, orientation of polyethylene chains due to flow under supercooling causes shear-induced crystallization and affects the final crystallinity of the product, with a strong impact on the mechanical properties of the product. Processing controlling parameters (e.g cooling and deformation rate) and the topology of polymers play an important role in crystallization kinetics. Low-field (time domain) NMR is a useful tool to quantitatively investigate and monitor the molecular dynamics in the phases of a crystallizing polymer [1]. Rheology provides access to the macroscopic mechanical properties of polymer melts [2], making it at promising idea to integrate the NMR measurement into it. Our home-built unique low-field Rheo-NMR setup as a combination of a permanent magnet with 0.7 T (30 MHz proton resonance) in a commercial high-end strain-controlled rheometer (Rheometrics/TA ARES) can measure a full rheological shear characterization (G’, G’’, LAOS, I3/1, FT-Rheology [3]) and the development of crystallinity at once [4]. Additionally, this technique allows for a direct correlation between the changes in the modulus as a function of the degree of crystallinity. Thus, it is possible to evaluate the effect of higher strain amplitudes on the gelation as a function of the crystallinity. The aim of this work is to investigate for the first time the crystallization of polyethylene variating molecular weight, additives and applied shear via low-field Rheo-NMR method. Key words: Rheo-NMR, Crystallization, Polyethylene References: [1] A. Maus, C. Hertlein, K. Saalwächter, Macromol. Chem. Phys. 2006, 207, 1150-1158. [2] T. Dötsch, M. Pollard, M. Wilhelm, J. Phys.: Condens. Matter 2003, 15, 923-931. [3] K. Hyun, C. O. Klein, M. Wilhelm, K. S. Cho, J.G. Nam, K. H. Ahn, J. S. Lee, R. H. Ewoldt, G. H. McKinley, Prog. Polym. Sci. 2011, 36, 1697. [4] V. Räntzsch, M. Wilhelm, G. Guthausen, Magn. Reson. Chem. 2015, DOI 10.1002/mrc.4219.