In this report, we describe our experience with transcatheter occlusion of congenital coronary arterial fistulas in adults. From November 1992 to November 1996, 5 symptomatic patients, aged from 47 to 70 years, underwent transcatheter occlusion of fistulas using a retrograde arterial approach. All had chest pain or dyspnea on exertion. Detachable balloons were used in 4 patients, and Gianturco coils in 1. Detachable balloons were implanted through a Debrun system, while the coils were implanted through a 5 French right coronary Judkins catheter. Both were passed through an 8 French guiding catheter (Amplatz II). Each patient had a single fistula. The fistulas originated from the right coronary artery in 3 patients, and from the circumflex artery in 2. They drained into the pulmonary trunk in 3 patients, into the right atrium in 1, andinto a bronchial artery in the other. All fistulas were occluded completely in the catheterization laboratory, and the procedures were uncomplicated. At follow up, 3 patients underwent coronary angiography, and there was no evidence of recanalization. Transcatheter embolization in adults of single congenital coronary fistulas with detachable balloons and coils is safe and effective and can be regarded as an acceptable alternative to surgery.