Twenty-five general practitioners collected information on 318 contacts of patients with a new episode of chest pain, discomfort or tightness. A list of complaints, signs and symptoms were checked, together with the initial diagnosis, made by the GP immediately after the physical examination. The initial diagnosis was compared to a follow-up diagnosis. The gain in certainty was also compared. The GP made a correct initial diagnosis in 82% of patients. In 8% there was a clinically important difference, and seven of 17 episodes of oesophageal disease were missed. For their initial diagnosis, the GP scored 74% certain, 20% uncertain and no diagnosis in 6%. For the final diagnosis, these figures were 88%, 8% and 4%.