Diagnosis of Takayasu arteritis (TA) is often delayed because of a non-specific clinical presentation. Ishikawa's criteria (1988) has been widely used for the diagnosis of this disease. Few modifications have been proposed in Ishikawa's criteria for the diagnosis of TA. The proposed modifications include: (a) removal of the obligatory criteria of age less than 40 years; (b) inclusion of characteristic signs and symptoms as a major criteria; (c) removal of age in defining hypertension; (d) deletion of the absence of aorto-iliac lesion, in defining abdominal aortic lesion; and (e) an addition of coronary artery lesion in absence of risk factors. The criteria proposed consists of three major criteria including left and right mid subclavian artery lesions and characteristic signs and symptoms of at least one month duration and ten minor criteria-a high erythrocyte sedimentation rate, carotid artery tenderness, hypertension, aortic regurgitation or annuloaortic ectasia, pulmonary artery lesion, left mid common carotid lesion, distal brachiocephalic trunk lesion, descending thoracic aorta lesion, abdominal aorta lesion and coronary artery lesion. Presence of two major or one major and two minor criteria or four minor criteria suggests a high probability of TA. When applied to 106 Indian patients of angiographically proven TA and 20 control subjects, it had a sensitivity of 92.5% and specificity of 95% that was higher than that of Ishikawa's criteria (sensitivity 60.4%, specificity 95%) and American college of Rheumatology criteria (sensitivity 77.4%, specificity 95%). Similarly, this criteria had a 96% sensitivity and 96% specificity in 79 Japanese patients of TA and 79 control subjects. Adoption of these criteria is expected to prevent the possibility of an under diagnosis of TA.