Our research had 2 aims, first, to determine if electrocardiographic early repolarization pattern anomalies (ERPAs) were more likely present among children and adolescents diagnosed with attention-deficit hyperactivity disorder (ADHD; n = 416) when compared with non-ADHD children (n = 187), and second, to asses if ADHD patients whose parents report severe ADHD psychometric scores were more likely to have ERPA in their surface ECG (electrocardiography) when compared with other ADHD patients with mild to moderate dysfunction or no dysfunction. In our unmatched case-control study, ERPA was recognized when there was an end QRS notch (J wave) or slur on the downslope of a prominent R wave with and without ST-segment elevation and the peak of the notch or J wave (Jp) ≥0.1 mV in ≥2 contiguous leads, excluding V1-V3 anterior lead, and QRS duration (measured in leads in which a notch or slur is absent) <120 ms or ST-segment elevation >0.1 mV in ≥2 contiguous leads, excluding V1-V3, and QRS duration <120 ms. The DSM-IV (Diagnostic and Statistical Manual of Mental Disorders, 4th edition) criteria were used to diagnose ADHD. Our data analysis suggested a significant association between ERPA presence and ADHD (n = 603, P = .020). Our logistic regression model suggests that patients with ERPA (n = 167) were 2.778 times more likely to have a diagnosis of ADHD after controlling for age, gender, and ethnicity (95% confidence interval for odds ratio 1.087-7.100, P = .033). Multiple regression models suggested that age, P < .001; gender, P < .001; ERPA, P = .004; and ERPA leads number, P = .022, were significant predictors of global parental ADHD worry scale. Hispanic and black ethnicity were not significant predictors. Consequently, the presence of ERPA should be reported in all ECGs done in children and adolescents for prospective behavioral phenotype and/or arrhythmia risk stratification analysis.