As a part of a study on the effective use of cultured oyster, oyster powder-added soybean pastes were prepared and its characteristics were examined. As the concentration of oyster powder added to commercial soybean paste was increased, the moisture level decreased, the crude and amino nitrogen content increased with no change in the salinity and titratable acidities. Also, the color of the soybean paste changed to a darker color as the concentration of oyster powder added to commercial soybean paste increased. Judging from the results of the above experiment and sensory evaluation, the optimal additive concentration of oyster powder to commercial soybean paste was revealed as 9%. The total amino acid content of oyster powder-added soybean paste was 2% higher than that of commercial soybean paste. The ratio of calcium and phosphorus of oyster powder-added soybean paste was about 1:2-2:1, an improvement in calcium absorption as compared to commercial soybean paste. Functional fatty acids, such as 20:5n-3 and 22:6n-3, were not detected in commercial soybean paste but detected in oyster powder-added soybean paste. The major free amino acids in oyster powder-added soybean paste were glutamic acid and aspartic acids. According to the above results, the nutritional, functional and taste properties of commercial soybean paste were improved while reducing preparation time of the housewife.