Intensive sport training is associated with physiologic cardiac remodeling, which are reflected on the electrocardiogram (ECG) most frequently as an increase of QRS voltages (Corrado et al., 2010). Because of the partial overlap of ECG signs of cardiac hypertrophy, athlete’s heart is often in the differential diagnosis with hypertrophic cardiomyopathy, which is the leading cause of sports-related cardiac arrest in young athletes. Though the criteria for abnormal QRS amplitude, requiring additional testing, have been recommended for pre-participation exams of athletes, the criteria have not considered the sport in which athletes participate. Therefore, we examined the effect of sports modalities on the computerized ECG QRS amplitude obtained in amateur athletes. Methods Computerized 12-lead ECGs were obtained in 131 male athletes (mean age 24.2±3.5 years) and 48 matched sedentary male controls (mean age 24.5±2.7 years) with a normal cardiovascular physical examination and without family and personal history of heart disease. Athletes were engaged in 9 different sports and were grouped into 4 categories: long-distance running, football/basketball/handball, judo/karate/taekwondo/boxing and dragon boat. The analysis focused on QRS voltages (R and S wave) of ECG 12 leads. Results ANOVA analysis yielded significant R wave amplitude differences between sports only in V2, V3, V4 and V5 (p<0.05). Specifically, the highest R was found in long-distance runners and the shortest one was found in gymnasts (V2, V4 and V5) or controls (V3). No significant amplitude differences among sports were found in S wave in all 12 leads (p>0.05). Discussion This descriptive study, which shows that R wave amplitude differences exist between sports, is a pioneering step toward the development of sport-specific criteria for abnormal ECG findings. The recognition of the existence of differences in ECG measurements between sports opens the door for further research which should link these ECG changes with structural cardiac changes. Although the significance of these differences in R wave amplitude between sports are not known, it is important to bear in mind the existence of these differences when testing athletes. Therefore, sport-specific ECG criteria for abnormal ECG findings should be developed to obtain a more useful approach to ECG screening in athletes.