The relationship of cigarette-smoking and nonfatal myocardial infarction (AMI) was evaluated using the case-control approach. Overall, the association was present for smokers of one and two packs per day, the standardized rate-ratio estimates being 1.5 and 1.7, respectively. The association was strongest in those who had a low risk score for AMI and particularly strong for people in the earliest (fifth) decade of age. People with diabetes and/or angina manifested no association between cigarette-smoking and AMI.