A retrospective study was conducted to examine whether emergency physicians can perform accurate ultrasonography that influences the diagnosis and treatment of selected disorders in the emergency department (ED). The physicians acquired a moderate level of expertise in sonography using a series of practical demonstrations and lectures. Patients with symptoms suggestive of cardiac, gynecologic, biliary tract, and abdominal vascular disease periodically underwent ED sonography. The initial interpretation was used as a diagnostic adjunct to subsequent therapy. The accuracy of positive sonographic findings was assessed by confirmatory testing, formal review, or confirmatory clinical course. Emergency physicians were able to diagnose correctly (1) the presence and approximate size of pericardial effusions, (2) the presence or absence of organized cardiac activity in patient with clinical electrical mechanical dissociation, (3) the presence or absence of intrauterine pregnancy in pregnant patients with lower abdominal/pelvic complaints, (4) the position of intrauterine devices in patients with suspected uterine perforation, (5) the presence of gallstones in patients with suspected biliary tract disease, and (6) the presence and size of abdominal aortic aneurysms in patients with pulsatile masses or unexplained abdominal pain. It was concluded that reliable sonography which influences diagnosis and therapy can be performed by emergency physicians and that sonography should become a standard procedure in EDs.