Medical evaluation of a chronic pain patient, who has very often seeked medical attention and has experience with useless treatments, represents a challenge for the physician. The visit to a pain specialistmaybe a glimmer of hope thatease his recuperation, provided the confidence is gained through a proactive, involved and dedicated attitude. It commences in the first visit by performing a comprehensive clinical history that encompass physical and phsycological issues. In this paper, general principles of the medical assessment of patients with chronic pain are discussed, including his past medical history, pain history and physical examination. The most important validated Pain scales and tools are also mentioned. The objective is to diagnose the source of pain while discarding severe pathology, to identify possible secondary gains and, therefore, to develop a treatment plan without missing the psycological sphere.