The case history of a 61-year-old male patient is described, who presented with severe stomatitis, conjunctivitis and leukocytosis. The diagnosis chronic lymphocytic leukemia (CLL) stage A (0) was made, for which no treatment was necessary. Progression of stomatitis and conjunctivitis and erythosquamous skin lesions with bullae and vesiculae formation developed. Under the diagnosis of bullous pemphigoid the patient was treated with corticosteroids. The histologic and immunofluorescence examination of a skin biopsy was compatible with this diagnosis, and antibodies to skin could not be detected in a first serum sample. Pseudomonas was cultured from all lesions, the corticosteroids were stopped and antibiotic treatment was started, without clear effect. Because of progression of skin lesions and debilitation, the patient finally declined all treatment and died five weeks after admission. Post-mortem examination showed enlarged lymphnodes in the cervical, aortal en iliacal areas, with histology confirming the diagnosis of CLL. Indirect immunofluorescence with the second serum sample showed auto-antibodies in high titer directed against the intercellular epithelial substance. Immunoblot studies showed binding with the classic target antigens in paraneoplastic pemphigus. Re-examination of the histologic skin specimen and the result of direct immunofluorescence were in retrospect compatible with the diagnosis of paraneoplastic pemphigus.