We report a case of lupus vulgaris with typical clinical and histological findings. Mycobacterium tuberculosis was not only identified by a conventional culture technique, but also by a recently established system which has been designed to detect mycobacterial DNA in formalin-fixed, paraffin-embedded tissue by polymerase-chain reaction (PCR). Because results can be obtained within days, the PCR-based technique may markedly facilitate the diagnosis of skin tuberculosis.