Direct immunofluorescence studies in granuloma annulare, necrobiosis lipoidica and granulomatosis disciformis Miescher are reported. In all 29 cases fibrillar deposits of fibrin in the necrobiotic areas have been found. Complement, mainly C3, was present in the region of the dermo-epidermal junction in 83% of the cases. Although the walls of the vessels in the superficial layers of the dermis showed a positive staining with antifibrinogen and complement, those around the necrobiotic areas were negative in most of the cases. The possible significance of these findings for the pathogenesis has been discussed.