The aim of our study was to evaluate the fibrinolytic system in patients with retinal branch vein occlusion (RVO). The following tests were carried out: prothrombin time, partial thromboplastin time (PTT), fibrinogen degradation products, euglobulin lysis time, fibrinogen, pasminogen, antithrombin III, alpha 2-antiplasmin and alpha 2-macroglobulin. Comparing the results of patients with those of normal controls, only the fibrinogen increase and PTT shortening were significantly different. All other tests taken into account were within normal limits. Only the patients without other associated diseases (diabetes or hypertension) showed a significant activation of fibrinolysis (either with respect to normal or to other RVO patient groups). In conclusion, no important fibrinolytic impairment was seen in our longstanding RVO patients. Fibrinolytic activation seen in patients without verified associated diseases may be related to the presence of a sound endothelium, still able to release plasminogen activators in response to RVO. The fibrinogen and PTT changes in RVO were probably due to other associated diseases.