Abstract Fat-tailed sheep come in various colours—most are either brown (tan) or black. In some, most of the body is white with the tan or black colour restricted to the front portion of the body or to just around the eyes, muzzle and parts of the legs. The Karakul breed is important for the production of lamb skins of various colours for the fashion industry. As well as the black and tan colours there are Karakuls bred for grey or roan shades, a white colour or one of the numerous Sur shades. In the Sur shades, the base of the birthcoat fibre is one of a number of dark shades and the tip a lighter or white shade. All these colours and many others are the result of the interaction of various genes that determine the specifics of the coat colour of the sheep. A number of sets of nomenclature and symbols have been used to represent the various loci and their alleles that are involved. In the 1980s and 1990s, a standardised set, based closely on those of the mouse and other species was developed. Using this as the framework, the alleles of the Extension, Agouti, Brown, Spotting, Pigmented Head and Roan loci are described using fat-tailed sheep (mainly Damara, Karakul and Persian) as examples. Further discussion includes other types of “white markings,” the Ticking locus and the Sur loci. co-workers (Roberts 1924, 1926, 1928, 1931; Roberts and Jenkins 1926; Roberts and White 1930a, 1930b—Wales/ UK), Dry (1924, 1926, 1927, 1936—UK) and others. Research into the colours of the Karakul began around the same time and was concentrated in the USSR, Germany and S.W. Africa (now Namibia). With the exception of the Karakul, most of the research was carried out in Europe. This included work on breeds of the Northern Short-tailed group (such as the Norwegian, Icelandic, Soay, Shetland, Manx Loaghtan and Gotland), on the Merino, on British breeds (such as the Welsh Mountain, Jacob and Wensleydale) and on other European breeds (such as the Corsican, Texel and the wild Mouflon). There has never been a review of the genetics of the coat colour as it applies to the various fat-tailed and fat-rumped breeds. While most of the research has involved the Karakul, there has been some reported in other breeds. The research that has been carried out has been reported using a number of different sets of nomenclature. There is, therefore, a need to review what is known of the genetics of coat colour as it applies to the fat-tailed and fat-rumped breeds and to present it using the standardised international nomenclature (COGNOSAG).