Biopsy specimens of papules taken from eight patients with polymorphous light eruption ( PMLE ) were examined by a direct immunofluorescence technique. Extensive intervascular and focal perivascular deposits of fibrin were detected in each case. Slight vascular deposition of C3 and IgM were observed in five and two patients, respectively. The lupus band test was negative in all cases. The findings suggest that venular injury with activation of the clotting system is involved in the development of lesions in PMLE .