Binuclear non-heme iron enzymes are a large group of enzymes that catalyze a variety of chemical reactions and are involved in numerous metabolic functions. In this review, the structural and biochemical properties of representatives of every class of this group of enzymes are described. The contributions of electron paramagnetic resonance-related techniques to our understanding of structure and reactivity of binuclear non-heme iron enzymes are discussed, and, where appropriate, supported by data obtained from complementary spectroscopic methods. This chapter is intended as a guide to illustrate the usefulness of electron paramagnetic resonance-related techniques in the study of these enzymes. Consequently, technical details were kept to a minimum.