The paper describes the purification and properties of two types of chondroitinases and two types of chondrosulfatases from *Proteus vulgaris* and *Flavobacterium heparinum*. Chondroitinase-ABC from *P. vulgaris* degrades chondroitin sulfates A, B, and C more efficiently than chondroitin and hyaluronic acid, and produces Δ4,5-unsaturated disaccharides. Two sulfatases, chondro-4-sulfatase and chondro-6-sulfatase, are separated from chondroitinase-ABC and are required for the hydrolytic desulfation of chondroitinase products. Chondro-4-sulfatase converts Δ4,5-unsaturated disaccharide 4-sulfate to the corresponding nonsulfated disaccharide and inorganic sulfate, while chondro-6-sulfatase converts Δ4,5-unsaturated disaccharide 6-sulfate. Chondroitinase-AC from *F. heparinum* is similar to chondroitinase-ABC but does not attack chondroitin sulfate B. The purification and properties of these enzymes are detailed, including their substrate specificity and inhibition by various compounds. The study provides insights into the metabolic fate of mucopolysaccharides and the potential use of these enzymes in determining the structure and quantity of mucopolysaccharides.The paper describes the purification and properties of two types of chondroitinases and two types of chondrosulfatases from *Proteus vulgaris* and *Flavobacterium heparinum*. Chondroitinase-ABC from *P. vulgaris* degrades chondroitin sulfates A, B, and C more efficiently than chondroitin and hyaluronic acid, and produces Δ4,5-unsaturated disaccharides. Two sulfatases, chondro-4-sulfatase and chondro-6-sulfatase, are separated from chondroitinase-ABC and are required for the hydrolytic desulfation of chondroitinase products. Chondro-4-sulfatase converts Δ4,5-unsaturated disaccharide 4-sulfate to the corresponding nonsulfated disaccharide and inorganic sulfate, while chondro-6-sulfatase converts Δ4,5-unsaturated disaccharide 6-sulfate. Chondroitinase-AC from *F. heparinum* is similar to chondroitinase-ABC but does not attack chondroitin sulfate B. The purification and properties of these enzymes are detailed, including their substrate specificity and inhibition by various compounds. The study provides insights into the metabolic fate of mucopolysaccharides and the potential use of these enzymes in determining the structure and quantity of mucopolysaccharides.