Medicine combines the characteristics of both a science and an art. The main objective is to cure the patient (or at least to alleviate symptoms). The first step of the global medical approach is to make a diagnosis, which will determine the therapy. Since Hippocrates, semiology, i.e. the study of both symptoms and signs, is crucial to make or guide the disease diagnosis. The development of more and more sophisticated medical technologies may lead to believe that semiology is not useful anymore in medical practice. It is absolutely not true because a careful semiology can provide precise diagnoses in a majority of cases or, at least, can lead to a limited differential diagnosis that helps in the selection of a few well defined complementary investigations. The aim of this article targeting mainly medical students is to emphasize the key rules of a well done medical interviewing, which should progress from an "analytical" approach to a "syndromic" approach, combining knowledge, know-how and self-management skills.