We thought of using black soybean in foods and tried making miso with it. Black soybean miso had a strong taste and functionality. The total nitrogen content of black soybean miso was 2% and that of yellow soybean miso was 1.83%. Protein content was 11.42% in black soybean miso and 10.45% in the yellow soybean miso, showing that black soybean miso had more total nitrogen and protein content. It was inferred that formol nitrogen and free amino acids were higher in black soybean miso, and black soybean miso contained more peptides and amino acids. The total sugar content and the amount of direct reducing sugar were slightly higher in yellow soybean miso. The acidities Ⅰ and Ⅱ and the content of organic acids and basic amino acids was higher in black soybean miso. Yellow soybean miso had more of calcium and magnesium, while black soybean miso contained more potassium, phosphorus, iron, and zinc. Black soybean miso had somewhat higher amount of γ-aminobutyric acid. Also, it had a slightly higher amount of polyphenol. Antioxidant activity was high in both the miso.