Lectin extracts were isolated from pea (PSA) and soyabean (SBA) seeds. In agglutination tests with human erythrocytes, SBA lectins showed higher activity than PSA lectins. The highest haemagglutination activity was observed with blood type AB, 50% lower activity with types A and 0, and the lowest, with type B. The experiment was performed on 30 male Wistar rats fed ad libitum a control diet or the same diet supplemented with PSA or SBA at a rate of 15 mg/day/rat for 14 days. Supplementation with lectins had a positive effect on feed intake and body weight gain, which differed significantly in the PSA group and numerically in the SBA group. PSA decreased the amylase activity in pancreatic juice and significantly decreased plasma glucose concentrations. Ca, P, Na, K, and Cl levels in pancreatic juice were similar in all groups. In rats fed the diets with lectin extracts, total pancreatic trypsin activity was significantly lower than in the control group and numerically lower in pancreatic juice. The results indicate that the effect of agglutinins from pea and soyabean seeds on pancreatic enzyme activity does not correlate with their agglutination activity.