The present invention relates to a method of producing a hydroxyalkyl starch derivative comprising reacting hydroxyalkyl starch of formula (I) at its reducing end which is not oxidized prior to said reaction, with a compound of formula (II) R'NH--R" (II) wherein R.sub.1-R.sub.2 and R.sub.3 are independently hydrogen or a linear or branched hydroxyalkyl group, and wherein either R' or R" or R' and R" comprise at least one functional group X capable of being reacted with at least one other compound prior to or after the reaction of (I) and (II), as well as to the hydroxyalkyl starch derivative as such, obtainable by said method, and to a pharmaceutical composition comprising said hydroxyalkyl starch derivative.