Physical mapping of the human prostate-specific membrane antigen gene (FOLH) has not been straightforward. Previously, localisations of this gene to either 11p11.2 or 11q14 have been described. This raised the possibility of the presence of more than one related FOLH gene in man. We now present detailed characterisation of the region around a FOLH gene in a 500-kb non-chimaeric YAC clone, putatively assigned to 11p11.2. This clone contains two known microsatellites, D11S1326 and D11S1357 which have been previously mapped unequivocally to the 11p11.2 region at 62.5 cM. This data strongly supports the original 11p11.2 localisation of FOLH. The YAC clone also has a putative EST at each of its ends and these have thus been physically positioned on this chromosome. However, the two regions previously highlighted at 11p11.2 and 11q14 are apparently extensively duplicated, as evidenced by the appearance of dual FISH signals with a number of different genomic probes selected across this 500-kb 11p11.2 region.