The current study compared three groups of participants with different levels of clinical experience in using the International Caries and Detection System (ICDAS) on occlusal surfaces. Thirty participants (faculty, graduate and undergraduate students), after a lecture and hands-on training session on two occasions, examined 60 occlusal surfaces previously examined by two criteria expert examiners. There were no significant differences between the groups for intra- and inter-examiner agreement for ICDAS severity or activity on occlusal surfaces as measured by kappa. Previous clinical dental experience does not seem to play a significant role in learning ICDAS.