Rapid differential diagnosis of circulatory failure (shock) with unknown etiology is a daily challenge in the field of emergency medicine. The Rapid Ultrasound in Shock (RUSH) protocol is well known since 2010. With the use of targeted steps, the 4 forms of shock (cardiogen, distributive, obstructive, hypovolemic) can be separated in a few minutes. The aim of the authors was to evaluate the usefulness of the Rapid Ultrasound in Shock protocol for the diagnosis of different forms of shock. The retrospective study included 123 critically ill patients admitted to the Emergency Department of Markusovszky Hospital, Szombathely, Hungary. Detailed records were obtained from all patients. From the 123 crirically ill patients, 64 patients suffered from circulatory failure, while the remaining patients had acute severe chest or abdominal pain, or respiratory failure. Based on the results of the first evaluation of the Rapid Ultrasound in Shock protocol in Hungarian patients, the authors conclude that, the bedside ultrasonography has a great value in emergency medicine, and this the protocol is suitable for its integration into patient care and education of emergency medicine.