Ultrasound examination is traditionally considered a safe and repeatable exam, but its use is highly operator-dependent. Because of this, lack of sufficient operator skills could lead to diagnostic errors and damage to patient safety related to unnecessary tests or interventional procedures. The indications for lung ultrasound include: diagnosis, quantification, and follow-up of different conditions for which acute respiratory failure or chest pain are the main clinical presentation. Clinicians should have theoretical and practical knowledge on: physics and technology of ultrasound, indications and methodology of ultrasound examination, normal thoracic anatomy identification by echography, and detection of signs of pleuro-pulmonary pathology. Consequently, according to international recommendations, core basic skills and minimum training recommendations for the practice of medical ultrasound and image acquisition are needed to ensure competence of clinicians using ultrasound.