Thirty-six cases of myocardial infarction during pregnancy, reported in the literature since 1922, together with three new cases from National Women's Hospital, Auckland, New Zealand, are reviewed. The incidence of the condition appears to be about 1 in 10 000 deliveries and the mortality is just under 30 per cent; the mortality appears to be highest in the puerperal patients, and surprisingly in those patients under 35 years of age. Present knowledge of the value of anticoagulants in the female patient with myocardial infarction, pregnant or otherwise, probably does not justify the use of such drugs, and the management of labour depends only on obstetrical circumstances.