Formate dehydrogenases (FDHs) represent a highly conserved subfamily of enzymes, characterized by a scattered taxonomic distribution. They are present in various bacteria (i.e., Firmicutes and proteobacteria) and eukaryotes (plants, yeasts, and fungi), and catalyze the NAD+-dependent oxidation of formate to carbon dioxide. The aspartate residue that defines the specificity towards NAD+ is conserved within the subfamily. FDHs play a pivotal role in methanol utilization in methylotrophic microorganisms (yeast and bacteria), supplying them with energy and reducing equivalents. As opposed to microbiological FDHs which function in cytoplasm, plant FDHs localize to the mitochondria and are key players in the cell stress response caused by both exogenic and endogenic factors.