Urticaria may be the only cutaneous manifestation of a leucocytoclastic vasculitis. We have studied fifty-five skin biopsies from patients with chronic urticaria to further characterize the histological findings and to demonstrate the existence of leucocytoclastic vasculitis. Urticarial vasculitis is a distinct entity showing urticarial skin lesions with leukocytoclastic vasculitis. Although clinical and histological aspects of chronic urticaria differ from those of vasculitis, some cases clinically diagnosed as urticaria but histologically characterized by vasculitis were described. Fifty-five patients with chronic urticaria were prospectively studied from 1996 to 1998. Biopsies were taken from recent urticarial lesions for histopathological analysis and also for direct immunofluorescence (DIP) studies. Histological findings in our patients with chronic urticaria were perivascular and/or interstitial lymphocytic (32 cases) or mixed (22 cases) infiltration. There was endothelial cell proliferation in 37 cases but true vasculitic changes were observed in only three cases. In evaluation of direct immunofluorescence, thirteen patients presented perivascular fluorescence. In our study, in all cases diagnosed as urticarial vasculitis, hives lasted less than 24 hours, so we believe that duration of the lesions should not be considered important criteria in performing a biopsy. Histopathological examination should be indicated in all cases resistant to therapy.