Intraventricular hemorrhage remains associated with high mortality and morbidity. Its most serious complication is posthemorrhagic hydrocephalus caused by multiple small blood clots obstructing the arachnoid villi. We treated three newborn infants (one term, two preterm) with posthemorrhagic hydrocephalus using recombinant tissue plasminogen activator, a thrombolytic agent, injected into the ventricles with a spinal needle. Sufficient fibrinolysis was achieved in these preterm patients. They all survived, and shunt surgery was only required in one. No adverse reactions or side effects have occurred. Intraventricular fibrinolysis with tissue plasminogen activator seems to be safe and effective for the treatment of intraventricular hemorrhage. However, controlled studies are needed for assessing treatment efficiency.