OBJECTIVE: To assess the value of necropsy examination in patients dying soon after cardiac surgery, particularly the proportion of clinical questions answered by the necropsy, the frequency of major unexpected findings, and the limitations of the procedure. DESIGN: A three year prospective study of necropsy examinations in adult patients dying before discharge or within 30 days of cardiac surgery performed under cardiopulmonary bypass in one hospital. SETTING: Tertiary referral centre. RESULTS: 123 of 2781 patients (4.4%) died in the early postoperative period, and necropsy examination was performed in 108 of these (88%). The mortality after emergency procedures (18%) was much higher than after routine operations (2.6%). The main causes of death were cardiac failure (52%), haemorrhage (14%), cerebral disease (6%), and pulmonary emboli (5%). The necropsy changed the stated cause of death in 16 patients (15%), and answered clinical questions in 24 of 38 patients. In 15 patients necropsy examination did not provide a full explanation of death. Most of these patients died of cardiac failure soon after surgery or were sudden unexpected deaths. CONCLUSIONS: Necropsy examination in patients dying early after cardiac surgery is valuable as it answers the majority of clinical questions, and shows unexpected findings in a significant proportion of cases.