A plasmici for the expression of the human growth hormone (hGH) gene was constructed using a novel combination of a cloning vector, pKEN024, containing the lipoprotein gene of Escherichia coli, ptrpED50chGH (containing cDNA to hGH mRNA), and a chemically synthesized DNA fragment that linked the hGH cDNA to the lipoprotein gene promoter and ribosome-binding site. The hybrid gene was expressed in E. coli, and its product accounted for about 10% of the bacterial protein synthesized. This product, methionyl hGH, was isolated and its biological activity was found to be similar to that of natural hGH obtained from cadavers. This procedure provides a means to obtain large quantities of biologically active hGH.