Fifty eight year old man, with dyspnea, fatigue and progressive angina underwent cinecoronarography, which showed an arterio-venous coronary-pulmonary fistula originating from the circumflex artery to the pulmonary circulation. We decided to occlude it percutaneously, using a detachable balloon technic. The occlusion was accomplished successfully. Clinical evolution was excellent and the follow-up cinecoronarography 6 months later showed the maintainance of the initial results.