PURPOSE: We compared the characteristics and outcomes of patients with ‘early repolarization’ electrocardiograms (ECGs) with those who had normal ECGs. METHODS: In 1983 to 1985, we collected photocopies of 2234 selected ECGs from 73088 patients undergoing health examinations. Excluding 153 ECGs with missing data or that were judged to be abnormal, the remaining ECGs were reinterpreted in 2000 by cardiologists as showing early repolarization (n = 670), or being borderline (n = 330) or normal (n = 1081). Characteristics and outcomes of persons with early repolarization ECGs were compared with those who had normal ECGs using analysis of variance, logistic regression, or proportional hazards models. Information on exercise was available in 325 patients. RESULTS: Patients with early repolarization were more likely to be male (81% [n = 583] vs. 33% [n = 360]), <40 years old (60% [n = 441] vs. 37% [n = 403]), black (48% [n = 384] vs. 26% [n = 280]), and more athletically active (mean [+/- SD], 10.4 +/- 1.3 hours per week of activity vs. 6.4 +/- 1.2 hours per week of activity) than those with normal ECGs. Patients with early repolarization were not more likely to be hospitalized (hazard ratio [HR] = 1.0; 95% confidence interval [CI]: 0.9 to 1.2) or to die (HR = 0.8; 95% CI: 0.6 to 1.2) during follow-up than those with normal ECGs. Outpatient diagnoses were not more common in those with early repolarization; arrhythmias were actually less common (P <0.01). CONCLUSION: Although especially prevalent in young, athletic, black men, early repolarization is not rare in other patients. The long-term prognosis of early repolarization is benign.