Blau syndrome is a rare autosomal dominant condition, typically defined by granulomatous polyarthritis, uveitis and skin eruption. Biopsy specimens demonstrate non-caseating granulomas in all lesions. We present a case of Blau syndrome associated with large recalcitrant leg ulcers. Biopsies taken in the leg ulcers of our patient systematically showed granulomas. Although leg ulcers have not previously been described as a part of Blau syndrome, we assume that the ulcerations in this case form part of Blau syndrome.