The Muir-Torre syndrome, in which sebaceous gland tumours occur in association with internal malignancy, is inherited as an autosomal dominant disorder. Many features of the syndrome are similar to those of the Lynch II cancer family syndrome, and thus the two disorders might share a common genetic basis. We typed two large families with DNA markers on chromosome 2p around D2S123, a site recently shown to be linked to the Lynch II syndrome. LOD scores at this locus demonstrated significant and tight linkage to D2S123, suggesting that defects in the same gene might give rise to both syndromes.