Obesity is increasingly prevalent in our society and medical consultations for evaluation and management of weight excess are frequent. Before considering a therapeutic strategy, a careful initial clinical assessment is mandatory. The diagnostic approach of an obese person should be similar as for any other chronic pathology. The objectives of the present clinical description are to report the main steps of an exhaustive anamnesis, the signs to be more specifically detected at the clinical examination and the other useful investigations to be programmed at first glance in a person who is visiting his/her medical doctor because of obesity. Based upon the data collected during this careful evaluation, therapeutic modalities may be defined, ideally in the frame of a multidisciplinary approach.