This review provides an overview of the current status and future directions of the use of biohydrogels (i.e., hydrogels obtained from biopolymers) as heterogeneous catalysts and/or supports for catalytic metal nanoparticles. This review collects a wide variety of biohydrogels used in catalytic applications, including gels made of polysaccharides (chitosan, alginate, carrageenan, dextran, agarose), proteins (gelatin, silk fibroin, ferritin) and nucleic acids (DNA). Additionally, the most significant features about the recyclability of these materials, their structural properties and the type of reactions that they catalyze are discussed. (C) 2018 Elsevier Ltd. All rights reserved.