The study concerns 17 eyes which, following vitrectomy, were given an injection of 25 micrograms of tissue plasminogen activator (tPA). Of these 17 cases, ten showed a severe fibrin formation in the anterior chamber, 3 cases showed vitreous hemorrhage (one of them with hyphema), 2 had fibrin formation and cellular proliferation, while in one case tPA was injected at the end of the vitrectomy because of perisilicone proliferation and in one case because of fibrin depositions on the intraocular lens. The tPA was injected into the anterior chamber (10 eyes) or into the vitreous cavity (7 eyes). The follow-up period ranged from 4 to 15 months (mean period 9 1/2 months). Fibrinolysis was noted in the 10 cases with fibrin formation in the anterior chamber. Fibrin dissolution was achieved within 3-4 hours. None of these cases presented a recurrence throughout the follow-up period. Positive results were observed also in the case with perisilicone proliferation. On the contrary in 3 cases with postvitrectomy hemorrhage the hemorrhage persisted unchanged. Also in 2 cases with fibrin formation and cellular proliferation on the anterior and posterior surface of the iris the tPA injection proved ineffective. Both cases developed traction retinal detachment (TRD) due to anterior proliferative vitreoretinopathy (PVR). In the case with fibrin depositions on the intraocular lens the situation remained unchanged. Any complications observed in our case proved to be mild and transitory.