AbstractJeotgal (醢) is a traditional Korean fermented food with thousands years of history with kimchi and other jang (fermented soybean products, 醬). The history was proved by research from historical literature and antique architecture. Jeotgal was developed along with jang (豆醬), fish jang (魚醬), meat jang (肉醬) as a part of jang (醬) up to the Chosun Dynasty and it was always offered during the ancestral rites or ceremonies. According to antique documents written by women, jeotgal had been used as seasonings or condiments that were popular especially for women rather than as food served for ancestral rites. In Southeast Asia and other countries, jeotgal uses varieties of fish and seafoods to provide rich and varied flavors, and thanks to the next generation sequencing technology, we can identify microorganisms that are involved in the fermentation process. Major microorganisms in jeotgal are Bacillus, Brevibacterium, Micrococcus, Pediococcus, Pseudomonas, Lactobacillus, Leuconostoc, and Halobacterium. Recently, much research on various health function of jeotgal has been conducted, reflecting increasing interest in the safety and the functionality of jeotgal. Many reports on functionalities of jeotgal such as supplying essential amino acids, and having antioxidant and antitumorgenic have been published recently. Because of the diverse flavor, types, and their function, jeotgal is expected to continue to develop as an important seasoning in the world sauce market.