To utilize oyster cannery processing waste water effectively, this study was carried out to prepare instant powdered soup using oyster wash water. Instant powdered soup from oyster hot-water extracts (HWE) was prepared by mixing oyster spray-dried hot-water extracts (15 g) with table salt (5 g), cream powder (19 g), milk replacer (12 g), wheat flour (20 g), corn flour (15 g), starch (5 g), glucose (7.5 g) and onion powder (1.5 g). In preparing instant powdered soup from oyster wash water (OWW), powder from oyster spray-dried wash water instead of the spray-dried hot water extracts, was added and other additives were added in proportion to those in the HWE. The OWW consists mainly of carbohydrates (71.1%). It was not different from the instant powdered soup from hot-water extracts. The volatile basic nitrogen, vaible cell counts, coliform group of instant powdered soup from oyster wash water contains 29.4 mg/100g, $4.6{ imes}10^4;CFU/g$, <18 MPN/100g, respectively and its water activity has 0.246. So it was a hygienically safe and conservable instant food. The main fatty acid of OWW was 16 : 0 and 18 : 1n-9. Its chemical score of protein was 59.4% and its main inorganic matter was iron. According to a sensory evaluation, in contrast to the HWE, the OWW had a slightly lower aroma but better taste. It was concluded from the above chemical and sensual evaluation that the oyster wash water can be used as a flavor enhancer for instant powdered soup.