The present invention relates to hydroxyalkyl starch conjugates and a method for preparing the same, the hydroxyalkyl starch conjugate comprising a hydroxyalkyl starch derivative and a cytotoxic agent, the cytotoxic agent comprising at least one primary hydroxyl group, wherein the hydroxyalkyl starch is linked via said primary hydroxyl group to the cytotoxic agent. The conjugates according to the present invention have a structure according to the following formula HAS′(-L-M)n wherein M is a residue of the cytotoxic agent, L is a linking moiety, HAS′ is the residue of the hydroxyalkyl starch derivative, and n is greater than or equal to 1, and wherein the hydroxyalkyl starch derivative has a mean molecular weight (MW) above the renal threshold and a molar substitution (MS) in the range of from 0.6 to 1.5.