Abstract: The goal of this study was to purify bovine pepsinogen by a simple method allowing the preparation of large amount of pure protein. The purified protein and antisera are needed to develop diagnostic methods for further investigations in animals susceptible of gastric disorders or helminthosis. Pepsinogen isoforms were separated from extracts of bovine fundic mucosa by ammonium sulfate precipitations and chromatography on DEAE and hydroxyapatite. The isoforms showed a high activity in indirect proteolytic assay. Sequence analysis gave the following amino acid sequence SVVKIPLVKK for fraction 1, 2 and SVVKIPLVKKKSLRQNLIENGKLKE for fraction 3. The Mass spectrometry revealed isoforms with different masses from 39,864 to 40,181 Da. The estimated organic phosphate content ranged from 0.98 to 3.9 moles of phosphate per molecule. The protocol, with few steps, gave consequent quantities of pure and active protein available for further studies including the development of RIA and ELISA as diagnostic tools in gastrointestinal diseases.