Sulf-1 and Sulf-2 are endo-acting extracellular sulfatases. The Sulfs liberate 6-O sulfate groups, mainly from N, 6-O, and 2-O trisulfated disaccharides of heparan sulfate (HS)/heparin chains. The Sulfs have been shown to modulate the interaction of a number of protein ligands including growth factors and morphogens with HS/heparin and thus regulate the signaling of these ligands. They also play important roles in development and are dysregulated in many cancers. The establishment of the expression of the Sulfs and methods of assaying them has been desirable to investigate these enzymes. In this chapter, methods to express and purify recombinant Sulfs and to analyze HS structures in an extracellular fraction of HSulf-transfected HEK293 cells are described. The application of these enzymes for ex vivo degradation of an anti-HS epitope accumulated in the brain of a neurodegenerative disease model mouse is also described.