Low back pain is a frequent symptom-related reason for visits to a general physician. In case of acute low back pain, the only situation that requires a radiologic exam is when <red flags> are present. This article specifies which anamnestic symptoms and past medical events are to be considered as such, and suggests what kind of radiologic exam should be done depending on the situation. It also mentions the psycho-social factors that favour a chronicisation of the problem and that should be identified in order to be taken care of. When low back pain becomes a chronic condition, there is a lack of scientific evidences/evidence based medicine and the actual recommendations whether or not to ask for imaging studies are based upon experts opinions. Medical follow-up is essential.