The study was undertaken to examine the immunogenic potential of pea protein of Polish variety Rodan and its trypsin hydrolysates differing in degree of hydrolysis. The physicochemical characteristic of pea protein extract and its hydrolysates, DH 2.0 and 5.0, were determined by SDS-PAGE electrophoresis, chromatofocusing, affinity chromatography, and sequential analysis. The immunogenic properties of pea protein and its trypsin hydrolysates, DH 2.0 and 5.0, were investigated by direct and competitive ELISA methods. The results confirmed that protein extract is a stronger immunogen than hydrolysates, while hydrolysate DH 2.0 was a stronger immunogen than DH 5.0. The dominant antigen isolated from pea protein extract and both trypsin hydrolysates had a molecular weight of about 20 kDa and was in the glycoprotein fraction. The N-terminal sequence of this antigen was determined to be: Thr-Glu-Thr-Thr-Ser-Phe-Leu-Ile-Thr-Lys-.