Syncope is a common problem in primary care practice that presents a diagnostic challenge. Fortunately, the initial evaluation not only identifies the cause in most patients with an identifiable cause, it also defines the prognosis for these patients. A systematic history, physical examination, and 12-lead ECG are the foundation of this evaluation and provide the most cost-effective diagnostic strategy. When signs and symptoms indicate a neurologic, cardiac, or carotid sinus problem, diagnostic procedures such as angiography, electroencephalography, cardiac catheterization, echocardiography, or carotid sinus massage should be added, but only as necessary to confirm the diagnosis. At the University of Cincinnati, we monitor patients with syncope of unknown origin with 24-hour ambulatory ECG recording and interpret the results as outlined in table 2. If not referred for cardiac or neurologic consultation, these patients are evaluated every three months for a year. This approach can minimize unnecessary testing and improve patient care.