Vasculitis associated with malignancy is uncommon, with the most well-known association being that between hairy cell leukaemia and polyarteritis nodosa. The less common association of vasculitis and solid tumours usually involves a cutaneous leukocytoclastic vasculitis. We report a patient with Duke's C adenocarcinoma of the sigmoid colon with associated necrotizing vasculitis of the mesenteric arteries and postulate that local factors may predominate in its pathogenesis.