Thromboangiitis obliterans (TAO), or Buerger disease, is a segmental occlusive inflammatory disorder of the arteries and veins, and etiopathogenesis is still obscure. It is strongly connected to the use of tobacco products, especially smoking. Smoking cessation is obligatory for success of the medical treatment. In the current study, we investigated the prevalence of endothelial nitric oxide synthase (eNOS) 894 G-->T and endothelin-1 (ET-1) 8000 T-->C polymorphisms in association with TAO to reveal any possible involvement in the TAO pathophysiology. The T allele of the eNOS 894 G-->T polymorphism was found to be associated with the prevention of TAO.