Probiotics are living microorganisms providing health beneficial effect to the host (1). Probiotics have been used for the treatment or prevention of various diseases related to diarrhea (2), cholesterol (3) immune function (4), and inflammatory bowel disease (5). In addition, recent study also presents that probiotic bacteria in the Bifidobacterium and Lactobacillus genera are able to have therapeutic effects in the patients of psychological disorders, such as depression, anxiety, and memory (6). Lactobacillus casei is a Gram-positive bacterium that naturally inhabits the human and animal gastrointestinal and mouth organs (7). As its name implies, this heterofermentative microorganism is the dominant species present in ripening cheddar cheese (8). In probiotic aspects, L. casei showed beneficial roles in the activation of the gut mucosal immune system (9), treatment of diabetics (10), and chronic constipation (11). In the previous study, we isolated L. casei LC5 strain from fermented dairy products, which showed immune regulatory functions, especially, therapeutic effect on atopic dermatitis as a member of complex probiotics (12-14). In order to gain better insight of the probiotic effect on atopic dermatitis, we analyzed the genome sequence of L. casei LC5. According to the report of NCBI Genome, 1 more than two hundreds of Lactobacillus organisms are sequenced and their beneficial properties derived from genomic information are used in the food industry. However, the available genomes of L. casei strains as members of health promoting probiotics are still insufficient. Furthermore, L. casei strains are frequently confused with the closely related strains such as Lactobacillus paracasei and Lactobacillus rhamnosus. Therefore, comparative study in a whole genome scale is required to clarify taxonomic association of L. casei LC5 as well as its functional characteristics. The availability of the genomic information of L. casei LC5 will aid as a basis for further in-depth analysis of the probiotic function of L. casei strains.