Anti-p200 pemphigoid is a rare subepidermal blistering disease associated with autoantibodies against a 200kDa protein, reportedly corresponding to laminin γ1. However, direct evidence of the pathogenic potential of these antibodies is missing. We have followed up a patient with anti-p200 pemphigoid for five years. During this period she experienced a total of three generalised relapses. Quantifying our patient’s autoantibody concentrations against laminin γ1 by ELISA throughout the course of her disease we demonstrated a clear correlation with disease activity, thus providing first evidence of the possible pathogenic role of antibodies against laminin γ1 in anti-p200 pemphigoid. Further analysis by Western blotting revealed the occurrence of additional autoantibodies against α3 chain of laminin 332 1½ years after diagnosis, suggestive of intermolecular epitope spreading. Yet, the clinical appearance was unchanged and mucous membranes remained unaffected at any stage of the disease.