Diamagnetic biological materials of various origins (e.g., prokaryotic and eukaryotic microbial cells, lignocellulosic materials, food wastes, soluble and insoluble biopolymers etc.) can be magnetically modified in order to obtain smart biomaterials exhibiting an appropriate response to external magnetic field. Magnetic modification of originally nonmagnetic biological materials is usually based on the attachment of magnetic iron oxides nano- and microparticles on the surface or within the pores of the treated material, or by their entrapment in the gel structure. Magnetic modification can be performed using different procedures, e.g., by magnetic fluid treatment, mechanochemical synthesis and by direct or indirect microwave assisted synthesis. This short review will summarize magnetic modification procedures developed by the authors and applications of advanced magnetically modified biomaterials as adsorbents of both organic and inorganic xenobiotics and radionuclides, affinity adsorbents for isolation of target biomolecules, carriers for various affinity ligands, biologically active compounds and cells or whole-cell biocatalysts. The potential of magnetically responsive biomaterials will increase in the near future.