Lack of appetite is a common problem in elderly people which could lead to the risk of malnutrition. Soup-based product formulation and supplementation for the elderly is an interesting and convenient way to maintain nutritional status. Hence, this study aims to develop ready-to-eat (RTE) soup and instant soup powder using common agricultural commodities. The results indicated that among all formulations, the F7 formula comprised brown rice (15 g), pumpkin (32.5 g), sweetcorn (12.5 g), red tilapia (17.5 g), rice bran oil (1.0 g), and water (21.5 g) with energy ratio (C:P:F) of 58:23:20 receiving the highest sensory scores. The selected formulation (F7) was also transformed into instant powder and both RTE soup and instant powder were evaluated for nutritional composition and storage stabilities at 5 °C and 25 °C, respectively. The nutritional composition analyses indicate that 100 g of RTE soup consists of 13.8 g carbohydrates, 4.9 g proteins, 1.8 g fats, and 1.5 g dietary fibers; the soup is also a rich source of antioxidants and β-carotene. Storage studies suggested that the content of β-carotene and antioxidant activity of both (ready-to-eat and instant powder) types of soup decreased with increasing storage time, while a slight increase in yeast and mold count (<50 cfu/g) was noted. Most importantly, no pathogenic bacteria were detected in ready-to-eat and instant soup during the storage study of 6 weeks at 5 °C and 6 months at 25 °C, respectively. In terms of the high nutritional composition and functional value of the product, 4 weeks of storage at 5 °C and 4 months of storage at room temperature were suggested for ready-to-eat and instant powder soup product, respectively.