Lyophilized bovine recombinant placental lactogen although stable at room temperature for several weeks, should be stored desiccated below -18 degree C. Upon reconstitution of bovine recombinant placental lactogen at > 0.1 mg/ml and up to 4 mg/ml and filter sterilization bovine recombinant placental lactogen can be stored at 4 degree C for several weeks.