Hydrogels are considered as interesting systems for the delivery of pharmaceutically active peptides and proteins because of their good tissue compatibility and possibilities to manipulate the permeability for solutes. In this study the release of three model proteins (lysozyme, BSA and IgG) from dextran hydrogels, which varied in water content and crosslink density, was investigated.Dextran hydrogels were obtained by a free radical polymerization of aqueous solutions of glycidyl methacrylate derivatized dextran (dex-GMA) using ammonium peroxydisulphate and N,N,N 1 ,N 1 -tetramethylethylenediamine as initiating system. The characteristics of the hydrogels could be manipulated by the concentration of the polymerizing dex-GMA solution and the degree of GMA substitution. Protein loaded hydrogels were obtained by dissolving the protein in the dex-GMA solution prior to the polymerization reaction. It was shown that, as expected, for a given gel the release decreased with increasing protein molecular weight. Moreover, it appeared that for a given protein the release decreased with decreasing water content of the gels. The release of the proteins could be effectively described by the free volume theory in gels with high water contents. On the other hand, in gels with low water contents screening effects occurred, indicating that the hydrogel mesh size approached the protein diameter.Hydrogel mesh sizes were also estimated from swelling data using the Flory-Rehner theory. This approach, however, resulted in an underestimation of the actual hydrogel mesh size as derived from release experiments.In conclusion, the release of proteins from dextran hydrogels can be manipulated over a large range by the gel characteristics, among which the water content and the crosslink density. These hydrogels are therefore suitable delivery systems for peptides and proteins.