Bovine vitreous body and aorta contain extractable Leukocyte elastase inhibitors, which were purified by gel filtration and affinity chromatography on agarose-pancreatic elastase. The purified inhibitor preparation from aorta was resolved by polyacrylamide gel electrophoresis into a main band migrating slightly faster than commercial Trasylol and a more weakly stained band migrating close to chymotrypsinogen. The purified inhibitor preparation from both sources inhibited, in a competitive fashion, purified human leukocyte elastase and was ineffective against bovine trypsin and leukocyte cathepsin G or collagenase. These inhibitors from vitreous body and aorta were distinguishable by several criteria from serum inhibitors.