A method of producing a hydroxyalkyl starch (HAS) derivative, comprising a) reacting optionally oxidized hydroxyalkyl starch with a compound (D) comprising at least two functional groups —O—NH2 or a salt thereof, and b) reacting the hydroxyalkyl starch derivative obtained in step a) with a compound (L) comprising at least two functional groups W1 and W2 independently selected from the group consisting of an aldehyde group, a suitably protected aldehyde group, a keto group, and a suitably protected keto group.