Information is limited on the co-existence and prognostic association of the ischemic electrocardiogram (ECG) and blood pressure. Prospectively collected data sets from 28,118 examinations in the Copenhagen City Heart Study were analyzed for cardiac morbidity and mortality for a 5.9-year follow-up. The prognosis of the ECG, independently of blood pressure, was examined. The Cox proportional hazard model was employed to evaluate the prognostic implications of ECG findings and relative risk was adjusted for age and multivariately adjusted for traditional cardiovascular risk factors. End-points were (1) fatal and non-fatal ischemic heart disease (IHD) events and (2) cardiovascular disease (CVD) mortality. During a total follow-up period of 166,471 person years (mean: 5.9 years) 1.481 IHD events were recorded and 1.051 CVD deaths. The relative risk of an ischemic ECG was independent of the blood pressure level. The multivariately adjusted relative risk for fatal and non-fatal IHD for the ischemic ECG was 1.70 (95% CI: 1.39-2.09, p < 0.001) in women, and 1.96 (95% CI: 1.67-2.30, p < 0.001) in men, and for CVD mortality 1.71 (95% CI: 1.34-2.17, p < 0.001) in women and 2.08 (95% CI: 1.74-2.49, p < 0.001) in men. An ECG with left ventricular hypertrophy (LVH) and ST-depression was the finding with the highest risk for future events. LVH by ECG voltage-only was associated with no statistically increased risk, except for men treated for arterial hypertension.