The role of ADAM-8 in cancer and inflammatory diseases such as allergy, arthritis and asthma makes it an attractive target for drug development. Therefore, the catalytic domain of human ADAM-8 was expressed, purified and crystallized in complex with a hydroxamic acid inhibitor, batimastat. The crystal structure of the enzyme-inhibitor complex was refined to 2.1 Å resolution. ADAM-8 has an overall fold similar to those of other ADAM members, including a central five-stranded β-sheet and a catalytic Zn(2+) ion. However, unique differences within the S1' binding loop of ADAM-8 are observed which might be exploited to confer specificity and selectivity to ADAM-8 competitive inhibitors for the treatment of diseases involving this enzyme.