The high-resolution NMR solution structure of the catalytic fragment of human collagenase-3 (MMP-13) was used as a starting point for structure-based design of selective inhibitors for MMP-13. The major structural difference observed between the MMP structures is the relative size and shape of the S1' pocket where this pocket is significantly longer for MMP-13, nearly reaching the surface of the protein. On the basis of the extended nature of the MMP-13 S1' pocket an inhibitor potent and selective for MMP-13 was designed from an initial high throughput screening (HTS) lead. CL-82198 was identified as a weak (10 muM) inhibitor against MMP-13 while demonstrating no activity against MMP-1, MMP-9, or the related enzyme TACE. The drug-Like properties of CL-82198 made it an ideal candidate for optimization of enzyme potency and selectivity. On the basis of NMR binding studies, it was shown that inhibitor CL-82198 bound within the entire S1' pocket of MMP-13 which is the basis of its selectivity against MMP-1, MMP-9, and TACE. A strategy utilizing this information was devised for designing new inhibitors that showed enhanced selectivity toward MMP-13. Our design strategy combined the critical selectivity features of CL-82198 with the known potency features of a nonspecific MMP inhibitor (WAY-152177) to generate a potent and selective MMP-13 inhibitor (WAY-170523). WAY-170523 has an IC50 of 17 nM for MMP-13 and showed > 5800-, 56-, and >500-fold selectivity against MMP-1 MMP-9, and TACE, respectively.