In a large epidemiological survey, 10,880 men aged 35 to 57 years were screened for ectopic ventricular activity and estimated risk of future coronary heart disease death. A 2-minute lead I electrocardiogram (ECG) was recorded for each man, together with measurement of serum cholesterol, blood pressure, and the number of cigarettes currently smoked. Ventricular premature beats (VPB) occurred in 540 (4.96%) men; of these 459 (4.21%) were uniform, while complex forms were detected in only 7/1000 men. VPB occurring with a frequency of greater than or equal to 10 in the 2-min recording were also rare, occurring in 9/1000 men. No relation was found between the frequency of simple or complex VPB and estimated coronary risk status or between the prevalence of VPB and the individual risk factors of diastolic blood pressure, cholesterol, or cigarette smoking. There was, however, a strong positive association between VPB and the level of systolic blood pressure, and between VPB and increasing age. The lack of association between VPB and overall coronary risk status indicates that myocardial "ischemic" changes in high-risk men may not have progressed sufficiently to alter ventricular excitability or to increase the frequency of VPB.