Cryptosporidium spp. are protozoan parasites that can cause significant gastrointestinal disease in humans and animals. Cryptosporidium spp. are usually host-specific; cats are commonly infected with Cryptosporidium felis, but Cryptosporidium parvum and Cryptosporidium muris have also been reported (Scorza and Tangtrongsup 2010). The majority of the Cryptosporidium DNA amplified from 14,469 human faecal samples in the UK was Cryptosporidium hominis (51.4 per cent) or C parvum (44.0 per cent) (Elwin and others 2012). However, C felis (38 of 14, 469 samples; 0.26 per cent) was identified among the unusual genotypes that cause human infections in the UK (Elwin and others 2012). Cryptosporidium oocysts or antibodies were first detected in cats in Scotland in 1991-1995. These studies reported prevalence rates of Cryptosporidium spp. of 5.2 per cent (7 of 136), 10.1 per cent (10 of 99) and 12.3 per cent (7 of 57) in domestic, feral and farm cats, respectively (Mtambo and others 1991, Nash and others 1993). Anti-Cryptosporidium IgG, IgM and IgA antibodies were detected in 192 (74 per cent), 84 (33 per cent) and 67 (26 per cent) on 258 cats (Mtambo and others 1995). Recently, Cryptosporidium oocysts were not detected in 57 healthy kittens in Scotland (Gow and others 2009). Another study reported a 1 per cent prevalence rate (13 of 1355) in cats with gastrointestinal disease from the UK, the Isle of Man and the Channel Islands (Tzannes and others 2008). However, no study has genetically characterised the Cryptosporidium spp. from cats from this region. The purpose of this study was therefore to determine the prevalence of Cryptosporidium species in pedigree cats in the UK. Faecal samples were collected between November 2005 and January 2006 from cats that attended one of two pedigree cat shows in the UK. Samples passed by the cats during the show, and samples collected by the owners once they had returned home from the show were accepted for the study. The latter samples were posted for next day delivery, and on arrival in Scotland all samples were frozen at −30°C. The frozen samples were shipped, by air freight on cold packs, to Colorado State University, where the thawed samples were stored at 4°C until assayed. All samples were assayed by a commercial immunofluorescent assay