Fourteen children with a mean age of 9.7 months (range 0.1-34.0 months) and a mean weight of 5.4 kg (range 2.5-10.0 kg) received intravenous streptokinase following arterial thrombosis. A median loading dose of 1000 U/kg (range 750-4000 U/kg) was given followed by an initial median infusion rate of 1000 U/kg/hr (range 750-1000 U/kg/hr). If thrombolysis did not occur and the fibrinogen level remained within the normal range (1.5-4.5 g/l) the infusion rate was increased to a maximum of 3000 U/kg/hr. Thrombolysis was achieved in all cases a mean of 16.7 hours (range 2-44 hours) after the start of treatment. The mean fibrinogen level at thrombolysis was 1.11 g/l (range 0.28-2.25 g/l) compared with pretreatment levels of 2.12 g/l (range 1.4-3.05 g/l). Minor bleeding from arterial puncture sites occurred in 6 children (43%). Streptokinase is a safe and effective treatment for arterial thrombosis in children.