In this chapter, practical engineering strategies for recyclable magnetic materials for biomass conversion are discussed, starting with the synthesis and chemical functionalization of magnetic nanoparticles and nanoscopic materials. Nanoscale magnetic materials are attractive for the design of various catalytic systems because of their large surfaces, temperature-stability and easy (magneto-)recovery. The applications discussed here are focused on transforming lignocellulosic biomass to sugars (and subsequent biofuel), as well as feedstock chemicals. The breaking down of lignocellulosic biomass can be achieved by subsequent biomass pretreatment and fractionation. Tailored magnetic nanocatalysts can be used in both processes. An alternative strategy for generating low molecular sugars from lignocellulosic biomass is the use of enzymes (e.g. catalase) on magnetic beads. It is an attribute of all systems discussed that they can be recycled magnetically, thus decreasing the required costs of “green materials”.