An increase in the incidence of primary cardiac tumors has been reported since the development or enhancement of noninvasive imaging modalities. We identified 56 children with primary cardiac tumors. Forty-four (78%) children had rhabdomyomas, 6 (11%) fibromas, 1 (2%) pericardial teratoma, 1 (2%) epicardial lipoma, 1 (2%) multicystic hamartoma, and 3 (5%) unspecified tumors. The mean age at diagnosis was 19 ± 35 months (median 4.7 months, range 0.03 to 204 months), excluding 12 patients who were given the diagnosis before birth. Among 27,640 patients assessed for cardiac disease, the incidence of tumors was 0.06% (1980 to 1984), 0.22% (1985 to 1989), and 0.32% (1990 to 1995). Diagnosis was made in 55 of 56 patients by echocardiography. Catheterization was performed in five patients and magnetic resonance imaging in nine. No tumor-related deaths occurred. Nine patients had surgery because of hemodynamically significant obstruction or arrhythmias. Partial or complete regression occurred in 24 (54%) of 44 patients with rhabdomyomas. Overall, the prognosis was excellent. Individualized surgery allowed early safe treatment of symptomatic tumors. (Am Heart J 1997;134:1107-14.)