Cognitive biases can impede the utilization of logical/statistical strategies in clinical decision-making. This paper reports on research and educational findings using the Inventory of Cognitive Biases in Medicine (ICBM). The ICBM was administered to groups of medical students before their clinical years and to practicing physicians to determine (a) the extent of cognitive bias in medical decision-making and whether experienced physicians differed from novices, (b) whether cognitive bias varied by medical speciality and (c) whether awareness of cognitive bias in medical decision-making could be taught. Preclinical medical students' mean score (41%) was near the chance level (42%). While practicing physicians scored higher (49%), they also demonstrated considerable susceptibility to cognitive bias. Cognitive bias varied by medical speciality with internal medicine physicians (57%) scoring best on the ICBM. A controlled educational research study with preclinical medical students showed that learners exposed to a seminar on cognitive bias in medical decisionmaking scored better on the ICBM than their peers (55% vs. 41%, p < 0.001). Susceptibility to cognitive bias was found to be present substantially among both novices and experts in medicine, but carefully crafted educational strategies in both classroom and clinical settings may lessen the problem.