The conventional structure of undergraduate medical education makes the implicit assumption that a "sound basis" in the understanding of the basic science disciplines is an essential prerequisite for starting clinical studies. It further assumes that the context within which the facts are presented is appropriate to this purpose and that demonstration of basic science knowledge is sufficient for the commencement of clinical studies. The precise structure of the preclinical phase of the medical course varies slightly from medical college to medical college but in general remains not unlike that described by Abraham Flexner more than 70 years ago, with the exception that it now packs many more facts and details into a similar space. The time has come to question the assumptions and to review the objectives of studying the basic medical sciences and the competencies that a student needs in order to progress to clinical studies. The author in this article reviews the available data and concludes that there is a substantial need for reform of the aims, content, and context of the learning in medical school preceding the clinical years.