The past year has seen some notable publications in the field of vasculitis epidemiology. The appearance of reports from several different parts of the world has permitted comparisons to be made. In Europe, Wegener granulomatosis appears to be more common at high latitudes, whereas microscopic polyangiitis shows the reverse pattern. Kawasaki disease is most common in Japan. In China, the United States, and the United Kingdom, the incidence is lower, but the incidence appears to be increasing globally. Studies of infectious triggers continue to be disappointingly negative. Immunogenetic associations with cytokine polymorphisms are beginning to be reported.