A 45-year-old female patient with CML underwent allogeneic BMT and developed two episodes of acute GVHD. The first episode of acute cutaneous GVHD grade II (day +17) responded well to systemic CsA and steroids. During the second episode (around day +60) the patient developed erythroderma (grade III), and subsequently signs of lichen-planus-like GVHD. The patient did not respond to increased dosages of prednisolone and CsA. On day +89 extracorporeal photochemotherapy (ECP) was initiated. After four cycles, a significant improvement of erythroderma and lichen-planus-like lesions was documented, and after 12 cycles, a lasting complete remission was achieved. To our knowledge this is the first report of successful treatment of early-onset, lichen-planus-like GVHD after allogeneic BMT with ECP.