We studied the frequency, location, clinical and histopathological features, associated manifestations, and prognosis of vasculitides in a cohort of 667 SLE patients. Exclusion of patients with previous vasculitis or insufficient information left 540 patients, 194 of whom has vasculitis (incidence density: 0.053 new cases/person/year, cumulative incidence of 0.051 at one year, 0.232 at 5 years and 0.411 at 10 years). Vasculitis was confirmed by biopsy in 46 cases, by arteriography in five, and by both in three. A single episode of vasculitis occurred in 119 and two or more in 75 patients. Vasculitis was cutaneous in 160, visceral in 24, both in 10. In the first episode of cutaneous vasculitides, 111 had punctuate lesions, 32 palpable purpura, 6 urticaria, 6 ulcers, 8 papules, 5 erythematous plaques or macules confirmed with biopsy, 2 erythema with necrosis, and 1 panniculitis (plus small vessel vasculitis). Of 29 with visceral vasculitis in the first episode, 19 had mononeuritis multiplex, 5 digital necrosis, 3 large artery vasculitis of limbs, one mesenteric, and one coronary, more than one type could appear simultaneously or in subsequent episodes. Patients with vasculitis had longer disease duration and followup, younger age of onset of SLE, and were more frequently males than those without. Lupus manifestations associated with vasculitis in univariate logistic regression included myocarditis, psychosis, Raynaud's phenomenon, serositis, leukopenia, lymphopenia and pleuritis. Vasculitis also associated with the antiphospholipid syndrome. The strength of this association increased when patients with vasculitis confirmed by biopsy and/or arteriography were considered separately. Visceral vasculitis associated with increased mortality when controlled for age of onset and nephropathy.