Clinical use of radiotracer techniques in pediatric cardiology is increasing. Three basic methods being employed are first pass radionuclide angiocardiography, gated blood pool scanning and myocardial perfusion scintigraphy. These methods are rapid, safe and accurate. They are minimally invasive and result in a low radiation dose to the patient. The development of ultrashort-lived radionuclides (such as iridium-191m with a half-life of only 5 seconds), improvements in nuclear imaging instrumentation and numerical analysis should contribute to a further utilization of these methods.