Amphiphilic block copolymers are well established as building blocks for the preparation of micellar drug carriers. Over the past decade, the effectiveness of such self-assembled drug delivery devices has been demonstrated numerous times. This review will discuss two approaches that can be used to further improve the effectiveness of amphiphilic block copolymer-based drug delivery systems. The first approach involves the chemical modification of the block copolymer building blocks. Several examples will be discussed of amphiphilic block copolymers modified with crosslinkable groups in order to increase the stability of the micellar drug carriers, or of block copolymers containing specific ligands that could ultimately allow targeted drug delivery. The second approach to improve the performance of micellar drug carriers is the addition of auxiliary agents. To illustrate this approach, the feasibility of channel proteins and metal (nano)particles to improve temporal control over the drug release process is discussed. © 2001 Elsevier Science B.V. All rights reserved.