Fermented big eyed herring. Harengula zunasi, and slimy, Leiognathus nuchalis, were widely used and contributed in diet of people in southern coast of Korea. In this paper, in order to elucidate the taste compounds of fermented big eyed herring and slimy, the nucleotides and their related compounds, free amino acids, TMAO, betaine, total creatinine, and minerals were analyzed. In fermented big eyed herring, lysine, alanine, leucine, isoleucine and valine were dominant holding 88.6% of the total free amino acids while alanine, leucine, isoleucine and lysine in fermented slimy were dominant holding 84.4% of total free amino acids. In the nulceotide and their related compounds, hypoxanthine was the major component in both samples. The contents of betaine, TMA and total creatinine were 99.7mg%, 24.2mg% and 432.8mg% in fermented big eyed herring, 107.6mg%, 19.5mg% and 258.8mg% in fermented slimy, while the contents of TMAO appeared trace in both samples. In the minerals of both samples Na and Ca were dominant holding 37,471-45,100.8ppm, 14,117.1-19,948.1ppm, respectively. From the omission test and chemical analysis, it is concluded that the major taste compounds of fermented big eyed herring and slimy were amino acids such as alanine, lysine, leucine and isoleucine. Minerals, nucleotides and their related compounds, betaine and total creatinine acted as an auxiliary role in taste of both fermented samples.