Detachable latex balloons, preloaded coaxially in 4-F angiographic catheters, were used in eight patients, aged 6 weeks to 12 years. Successful placement of the balloon was achieved in six patients, in whom the feeding arteries arose in an oblique fashion from the aorta or main conducting arteries. Placement was not possible in two patients. No femoral or axillary arterial occlusions occurred as a result of these procedures. The balloon can be inflated up to 8 mm in diameter, passes readily through a 4-F introducer sheath, and can be retrieved, without detachment from the catheter, through the same sheath. A hemostatic side-arm adapter attached to the catheter permits angiography to be performed before balloon detachment. The disadvantages of the system include preparation time to hand tie the balloons, the operator experience required, and difficulty in navigating the balloon.