Although abalone is a commercially valuable marine product, its catch is declining year by year. Abalone cultivation is being carried out in many parts of the world for fishery resource management and commercial purposes, and there is a need for the development of feeds that can promote efficient growth in cultivation. In this study, we developed eco-feed for disk abalone (Haliotis discus discus Reeve) cultivation using soy pulp (okara), Japanese sake lees, and rice bran, which are by-products of food processing, as the main raw materials. The results of a 9-month feeding trial showed that the shell length, body weight, and nutritional components (free amino acids and fatty acids) of the developed diet-fed disk abalone were similar to those of the commercial solid diet-fed disk abalone.