Bovine eyes were dissected and separate pools of lens, lens capsule, cornea and vitreous were extracted in guanidine, subjected to ultrafiltration, and examined for their effects on collagenolytic activity. Although lens extract was not inhibitory, the cornea and vitreous both contained Inhibitors of collagenase. More inhibition was present in the filtrate of the vitreous than in the retentate, whereas the total amount of inhibition in the cornea was distributed almost equally between the two fractions. The inhibition observed was dose dependent. The partially purified inhibitors from cornea and vitreous blocked the activity of human skin and tadpole back skin collagenases, but they failed to inhibit the bacterial(Clostridium histolyticum)collagenase. The inhibitor was stable to heating to 60 for 30 minutes and to trypsinization.