A 24-hour telephone transmission service was established for pediatric echocardiography between a general hospital and a children's hospital 500 km distant. Studies were transmitted in real time for interpretation and diagnosis by a pediatric cardiologist. In the first 9 months of operation, studies were transmitted for 18 children with a median age of 5 months. Image and sound quality was excellent. Complete segmental diagnosis was made in 16 patients, and further study was needed in 2 others. In 8 of the 18 patients a new diagnosis was provided, and in 10 patients diagnosis was confirmed. Congenital heart disease was found in 12 patients, other heart disease in 2 and a normal heart in 4. The population included 2 fetuses whose echocardiograms showed hypoplastic left heart and intracardiac tumor. In 4 patients transport was avoided. This is the first report of echocardiographic transmission by telephone, which was shown to be clearly feasible, cost-effective and diagnostic. It provides emergency access to specialist expertise, and may avoid hazardous and expensive transport of ill children.