Currently more than twenty different matrix metalloproteinases (MMPs) and four tissue inhibitors of metalloproteinases (TIMPs) have been identified ( 1 , 2 ) by cDNA cloning. This chapter describes methods to purify collagenases (MMP-1, MMP-8, and MMP-13), gelatinases (MMP-2 and MMP-9), stromelysins (MMP-3 and MMP-10), macrophage elastase (MMP-12), and TIMP-1 and TIMP-2 from natural sources. These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.