OBJECTIVES: The goal of this study was to define electrocardiographic (ECG) and echocardiographic characteristics of adolescent African athletes. BACKGROUND: Recent observations in African athletes reported large prevalence of left ventricular (LV) hypertrophy and ECG abnormalities. No data, so far, exist for adolescent Africans, which comprise a growing proportion of competitive/professional athletes. METHODS: The study included 154 soccer players participating at the 8th African Under-17 Championship of 2009, representing Algeria, Burkina Faso, Cameroon, Gambia, Guinea, Malawi, Nigeria, and Zimbabwe. For comparison, 62 Italian players with similar ages, sport achievements, and training schedules were included. RESULTS: African athletes showed higher R5/S1-wave voltages than Caucasian athletes (48.6 ± 12.1 mm vs. 34.1 ± 8.9 mm; p < 0.01), larger prevalence of ECG LV hypertrophy (89% vs. 42%; p < 0.001), ST-segment elevation (91% vs. 56%; p < 0.001), and deeply inverted, or diffusely flat/biphasic, T waves (14% vs. 3% [p < 0.05] and 25% vs. 8% [p < 0.008], respectively). LV wall thicknesses were increased in Africans by 5% compared with Caucasians, and exceeded normal limits (≥13 mm) in 4 Africans but in no Caucasians. No athlete showed evidence of cardiomyopathies (i.e., hypertrophic cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy). On individual analysis, Algerians showed lower R/S-wave voltages compared with other African athletes. Increased wall thickness (≥13 mm) was observed only in sub-Saharian athletes (from Burkina Faso, Cameroon, and Niger). CONCLUSIONS: African athletes displayed large proportion of ECG abnormalities, including a striking increase in R/S-wave voltage, ST-segment elevation, and deeply inverted or diffusely flat T waves by adolescence. LV remodeling in African athletes was characterized by a disproportionate wall thickening than in Caucasians but similar cavity size. Finally, distinctive peculiarities existed in African athletes according to the country (and ethnic) origin.