Field-induced changes of the mesostructure of ferrogels and the resulting changes of their viscoelastic properties are investigated. As a model system pNIPAM hydrogels containing anisotropic hematite particles are used. Hematite aligns in magnetic fields provoking an elastic deformation of the hydrogel. Particle-matrix interactions are analyzed via orientational distribution functions of the particles. Field-dependent viscoelastic properties are studied by means of rheological and RheoSAXS experiments. Employing XPCS, in external fields the diffusive motion of the particles is investigated.