After many changes, Buerger's disease stands as an independent clinicopathologic entity, but a better understanding of Buerger's disease has been impeded by the lack of unanimous diagnostic criteria of the disease. Since specificity of Buerger's disease is characterized by peripheral ischemia of an inflammatory nature and with a self-limiting course, diagnostic criteria of Buerger's disease should be discussed from clinical point of view. Our clinical criteria for the diagnosis of Buerger's disease are: (1) smoking history; (2) onset before the age of 50 years; (3) infrapopliteal arterial occlusions; (4) either upper limb involvement or phlebitis migrans; and (5) absence of atherosclerotic risk factors other than smoking. Confident clinical diagnosis of Buerger's disease may be made only when all five requirements have been fulfilled. A set of strict and well-defined clinical diagnostic criteria is essential for any study of Buerger's disease to ensure the homogeneity of the selected patient population for valid comparisons.