In this retrospective review 102 Indian and 80 Japanese patients with Takayasu arteritis were compared in regard to their clinical manifestations and angiographic findings. Regardless of nationality, most patients were initially affected in their teens or twenties. Japanese patients were female in a larger ratio compared with the ratio in India. Clinically, the two groups exhibited several different features. More Japanese patients were found to be pulseless (P < 0.01) whereas many Indian patients were hypertensive (P < 0.01). Inflammatory conditions in Japanese patients were more severe (P < 0.01) and tended to be more prolonged than those in the Indians. More Japanese patients suffered from aortic regurgitation (P < 0.01), but Indians suffered from hypertension (P < 0.01). Angiographic findings revealed that the aortic arch and its branches were mainly involved in Japanese patients (type I, IIa) whereas the abdominal aorta and its branches were mainly involved in Indian patients (type IV). However, the diffusely involved type (type V) was the one most commonly found in both countries. From the analyses of vascular lesions in both Indian and Japanese patients, 510 and 396, respectively, different progressions of vasculitis are speculated. In Japanese patients, vasculitis generally occurs in the ascending aorta, the aortic arch, and/or its branches and extends into the thoracic and abdominal aorta, subsequently forming various complicated lesions with prolonged inflammatory activity. On the other hand, in Indian patients, vasculitis generally occurs in the abdominal aorta involving renal arteries, subsequently extending into the thoracic aorta within one or two decades, simple vascular lesions being formed. Data analysis suggests that this morbid condition progresses differently in India and Japan, in spite of some common etiologic factor(s).