The present invention provides a method for sterilizing a protein-containing bioerodible implant. The sterilization is accomplished using β-radiation, or high energy electrons. Following sterilization the implant can be used in a variety of methods for the sustained release of a therapeutic protein to treat a disease or condition in a human or non-human subject. The sterilization process is compatible with proteins containing one or more disulfide bonds or easily oxidized methionine residues.