Abstract: An improved size composition of a modified starch and polyvinyl alcohol especially useful as a textile size is disclosed. The modified starch is a hydroxyalkyl and tertiary amino alkyl starch with a D.S. of aminoalkyl groups between 0.02 to 0.30 and a M.S. of hydroxypropyl groups between 0.02 and 0.50. The ratio of polyvinyl alcohol: modified starch in the size composition varies between 1:9 and 9:1. The method of applying the size composition to yarn and the method of making the size composition are also disclosed. High amylose starch, as compared to common or waxy, is the preferred starch.