Two cases of Takayasu's arteritis associated with Crohn's disease of the colon are described, both of which occurring in young female patients. In the first case, the vasculitic process was widespread, involving the aortic arch, the abdominal aorta, the renal arteries and the left iliac artery, similar to the angiographic "Indian" pattern. The second case presented a typical "Japanese" aortic arch involvement. In the first patient, Crohn's disease appeared to have been present prior to Takayasu's arteritis, vice versa in the second case; steroid treatment, assigned for both diseases might, however, have modified their natural evolution. The association is rare. Moreover, the coexistence of two immune-mediated diseases in the same subject is unusual as they are generally considered to be independent. Hypotheses concerning their possible inter-relationship are advanced.