We report a child in whom multiple cardiac rhabdomyomas were identified on routine fetal ultrasonography. Molecular genetic studies identified the TSC2 gene missense mutation (E36; 4672 G>A, 1558 E>K TSC2). Both general and neurodevelopment of the patient have been normal. When last examined at age 6 years, he had no skin manifestations of tuberous sclerosis complex. Computed tomography of the brain revealed two periventricular calcifications consistent with the molecular diagnosis. This is the first report of molecularly confirmed tuberous sclerosis complex in a child with multiple cardiac rhabdomyomas and no other clinical manifestations of the disease. We propose that all cases of multiple cardiac rhabdomyomas in an infant be given a tentative diagnosis of tuberous sclerosis complex.