Background and objectives: Electrocardiogram is a commonly used procedure for diagnosis of heart disease. It is not known doctor skills nowadays and utility of intensive course electrocardiogram teaching. The objective is to evaluate the accuracy in the interpretation of electrocardiograms among residents and staff doctor and evaluate the usefulness of an intensive training course in ECG (one week, 20 hours long) with a standard rotation in cardiology unit. Methods: Participants were included prospectively and divided into two groups for analysis: Hospital Group (82 residents during their Cardiology rotation) and Course Group (71 residents and 41 staff physicians from the audience to a specific electrocardiogram course). They fill in 2 different questionnaires of 10 basic electrocardiograms: “Initial Test” at the beginning and “Final Test” at the end. We assign one point for each correct answer and zero for incorrect one (score range was 0 to 10 points). Results: The score achieved in the “Initial Test” (standard deviation) was 5.09(1.81). Residents obtained 5.28(1.8), and Seniors 4.4(1.6), p=0.006. In the “Final Test” score achieved was 5.91(1.9), Residents obtained 6.03(1.98) and staffs 5.48(1.7), p=0.104. We found no differences in the “Final Test” score between both ECG teaching methods after adjusting. Conclusion: Real ECG knowledge between doctors is poor. Residents obtained better results than staff at the beginning but at the end there were not statistic differences. Intensive course were similar to classical teaching method.