Abstract: Novel carboxymethyl-etherified starch derivatives and methods for manufacturing the same, and more particularly, to the novel carboxymethyl-etherified starch derivatives having a viscosity in 5% aqueous solution of 15.about.600 cps, when measured by a viscometer of the Hakke rotary type; a permeability in 0.1% aqueous solution of more than 95% at 623 nm, when measured by a UV spectrophotometer; viscosity values at a maximum temperature of 95.degree. C. and at a temperature cooled to 50.degree. C. of 6.about.304 BU and 6.about.720 BU, respectively when measured by a Brabender viscometer. The cool water-soluble carboxymethyl-etherified starch derivatives are prepared by the following steps: starches (such as corn, potato, wheat and rice are dissolved in organic solvents, such as, lower alcohol without hydrolysis, or hydrolyzed in the presence of inorganic acids, such as, hydrochloric acid or sulfuric acid at 25.degree. to 75.degree. C. for 30 minutes to 72 hours.