Based on the encouraging results obtained with extracorporeal photochemotherapy (EP) in the treatment of the exfoliative erythrodermic form of cutaneous T-cell lymphoma (CTCL), leukemic form, as well as other T-cell-mediated diseases we evaluated the therapeutic potential of EP in patients with chronic lymphocytic leukemia (B-CLL). Three patients with B-CLL were treated for a period of 1 year. Two patients showed stabilization of disease, as demonstrated by reduction in their peripheral white blood cell count, with one patient showing lymph-node resolution. A third patient with significant intolerance to previous chemotherapy did not respond within the observed period. No significant side effects of EP were observed. Our observations suggest that EP may have a positive effect on the course of B-CLL in selected patients. Additional clinical trials are warranted to further define the role of EP alone or in combination therapy in the management of B-CLL.