Six young-adult patients (19- to 32-years-old) are described: 3 men with temporally localized systemic vasculitis (thromboangiitis obliterans 2, Churg-Strauss angiitis 1) and 3 patients (2 men, 1 woman) with isolated temporal arteritis. Temporal arteritis in subjects under 40 years of age consists of either a temporal localization of systemic vasculitis (thromboangiitis obliterans or Buerger's disease, Churg-Strauss angiitis or polyarteritis nodosa) or a distinct entity of which only 12 biopsy-proven cases have been reported to date. The latter is differentiated from temporal (giant cell) arteritis of the older patient by a higher incidence in men, and the absence or rarity of general symptoms, ocular complications and an accelerated erythrocyte sedimentation rate. Two types of temporal arteritides in young adults seem to be distinguishable: an asymptomatic form with an isolated temporal nodule and a more symptomatic one. In some cases, temporal arteritis in young adults corresponds to a unique entity "juvenile temporal arteritis", which seems to be different from Takayasu's arteritis, localized forms of polyarteritis nodosa and Kimura's disease. Although its treatment remains difficult to define, therapy of the symptomatic form could include steroids, whereas the asymptomatic one seems to require only simple monitoring.