Poly(A)-containing mRNA of pepsinogen was isolated from total RNA of bovine gastric mucosa by oligo (dT)-cellulose chromatography and Sepharose 4B chromatography, and was translated in a wheat germ cell-free system. The translation products. were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and fluorography. A major translation product was pepsinogen which was synthesized in two different molecular forms with molecular weights of 45,000 and 43,000 daltons. The pepsinogen translated in the in vitro translation system had no autocatalytic activity. The peptidemaps of the translated pepsinogen which was digested by chymotrypsin and Staphylococcus aureus V8 protease were nearly identical with the corresponding peptide masps of standard bovine pepsinogen.