Abstract: This article describes an approach to an Intelligent Tutorial System - CARDIOLOG, specially developed to help in teaching electrocardiogram (ECG) interpretation to medical students. Although the system can be used as a self-learning tool, one of its main characteristics is the adequacy to classroom environment - a Professor module and many Student's modules. Medical students and professors, physicians and people interested on the subject will be able to form a solid knowledge base or complement their studies with CARDIOLOG. The activities rely on user-friendly interfaces, based on the questions/answers model, with the possibility of consulting reference (if enabled by the professor). Analysis of students' performance, reports and knowledge base maintenance tools are also available in CARDIOLOG. CARDIOLOG was implemented using Artificial Intelligence technologies, development using object methodology, Client/Server structure, 32-bit Windows platform.