Melkersson-Rosenthal (MRS) syndrome is characterized by a classical triad of recurrent or persistent orofacial swelling, peripheral facial nerve paralysis and lingua plicata. Granulomatous cheilitis (GC) is regarded as a monosymptomatic form of MRS. The exact aetiologies of MRS and GC are unknown. In this study we investigated the possible role of mycobacteria in these two conditions. A ribosomal RNA amplification-based Gen-Probe amplified Mycobacterium tuberculosis direct test was used to investigate the presence of M. tuberculosis complex in paraffin-embedded skin biopsy specimens from five patients with MRS and one patient with GC. Three of the six specimens were shown to be positive using this system; one of the positive specimens also showed positive Ziehl-Neelsen staining. These results suggest a possible mycobacterial aetiology for MRS and GC.