The ultrasound has become a very useful tool for the anesthesiologist because it complements and deepens the physical examination, ameliorating the clinical decision process. Among its many advantages are that is a bedside, abreviated exam, that avoids unnecesary transfers to other services, (of note in hemodinamically unstable Patients), besides is a radiation free method, repeatable as many times as needed. Its effectiveness for procedures is described, highlighting the central venous catheters and arterial lines placement. Also its diagnostic benefits, with accent on answering some specific questions. The full range of uses is described, incluiding: echocardiography, lung and pleura ultrasound, gastric ultrasound, extended FAST, airway, optic nerve sheath and the practical utility of each one.