Citrus canker caused by Xanthomonas citri subsp. citri is a bacterial disease of worldwide distribution occurring wherever citrus is grown. The disease attacks most of the varieties of citrus. Different strains of citrus canker have been reported throughout the world and the Asiatic strain is the most widespread and severe form. Disease symptoms on limes were observed in Basht (Kohgiluyeh and Boyer-Ahmad province). In order to identify the causal agent of the disease, infected parts of the plant, transferred to the laboratory and were squashed in sterilized water and cultured on NA and YDC medium. After 48 72 hours, gram negative bacteria with yellow colonies and negative oxidase, positive catalase and obligate aerobe were isolated. Some biochemical tests such as levan, tween 80, starch hydrolysis, Gelatin hydrolysis, Asculin and HR Tobacco and production of yellow pigment on YDC were positive. Meanwhile, Arginine dihydrolase, Lecithinase and production of fluorescent pigment on KB medium were negative. Also pathogenicity test on Mexican lime (Citrus aurantifolia) was performed. The bacterium produced erumpent, pustule-like lesions of typical Asiatic citrus canker syndrome after inoculation into Mexican lime. Based on the disease symptoms, phenotypic and pathogenicity tests, the isolates were identified as Xanthomonas citri subsp. citri. With the use of the specific primer M+ and M- all of the isolates were identified as a pathotype A. Only 9 isolates were identified as pathotype A* when specific primers Ms- and Ms+ was used. This is the first report of the disease and the causal bacterium in Kohgiluyeh and Boyer-Ahmad province.