A new class of diblock copolymers was synthesized from biodegradable poly(lactic acid) and poly(ethylene glycol)-monoamine. These polymers were activated by covalently attaching linkers such as disuccinimidyl tar-trate or disuccinimidyl succinate to the hydrophilic polymer chain. The polymers were characterized by H-1 NMR spectroscopy, C-13 NMR spectroscopy and gel permeation chromatography (GPC). These investigations indicated that the polymers were obtained with the correct composition, in high purities, and the expected molecular weight. By using dyes containing primary amine groups such as 5-aminoeosin as model substrates, it was possible to show that the polymers are able to bind such compounds covalently. The diblock copolymers were developed to suppress unspecific protein adsorption and allow the binding of bioactive molecules by instant surface modification. The polymers are intended to be used for tissue engineering applications where surface immobilized cell adhesion peptides or growth factors are needed to control cell behavior.