The sudden death of a child or teenager is a rare event with a profound impact on parents, family, friends and schoolmates. It often generates much publicity and instils fear in the parents of other healthy children. If the postmortem examination reveals a previously unsuspected cardiac abnormality, this raises the question of whether it could have been detected and death could have been prevented. If no cause is found at autopsy, and a cardiac arrhythmia is presumed to be responsible, there is no satisfactory resolution for the parents. Screening programmes for “young athletes” have been proposed in Europe and the USA based on the consensus views of experts and informed mainly by data from sudden deaths up to the age of 35 years.^w1 This review will examine the feasibility of detection of potentially fatal latent heart defects and the possibility of screening in children and teenagers.