The object of this study was to assess the ability of junior doctors in the accident and emergency department to detect electrocardiographic (ECG) abnormalities. The ECG's performed in this department were monitored over a 4 week period. The initial diagnosis by the accident and emergency doctor was compared with the report from the cardiologist on 126 ECG's which showed abnormalities. The error rate was 19.8%. Of those abnormalities which were graded as clinically significant only 2 (4.4%) were missed. The danger of missing acute changes is emphasized and proposals discussed which may reduce their frequency.