Paragangliomas may be inherited in an autosomal dominant manner either alone (as in PGL1, PGL2, and PGL3 syndromes) or as a component of a multiple tumor syndrome (as in von Hippel-Lindau disease and neurofibromatosis type 1). In this article, we describe 12 patients (7 male and 5 female) with an average age of 23 years from five unrelated families that manifested paraganglioma and gastric stromal sarcoma; the tumors were inherited in an apparent autosomal dominant manner, with incomplete penetrance. Seven patients had paraganglioma, four had paraganglioma and gastric stromal sarcoma, and one had gastric stromal sarcoma. The paraganglioma was multicentric and the gastric stromal sarcoma multifocal. Because of the rarity of gastric stromal sarcoma and its multifocality, the young age of the patients, and the unlikelihood of coincidental co-occurrence of paragangliomas and gastric stromal sarcomas, we suggest that a new syndrome exists with these two main components, a condition that is familial and distinct from the Carney triad. Published 2002 Wiley-Liss, Inc.