ABSTRACT The aim of this study was to determine the effects of the replacement of different levels of protein derived from soybean meal with that from peas in broiler diets on serum protein fractions. A corn-soybean meal basal diet was formulated as the control diet (Control=C) (NRC, 1994), and then pea was added to the control diet to replace 20% (P20) or 40% (P40) of the crude protein of the control diet. The diets were randomly fed to 12 pens per treatment, each housing five birds, for 42 days. Blood samples were collected from 36 birds (3 birds x 4 pens x3 treatments) and the serum protein fractions were separated. Gamma-globulin percentage was higher in group P20 compared with C and P40 groups. Total protein, beta-globulin, and gamma-globulin concentrations were significantly higher in group P20 compared with those of both control and P40 group (p<0.05).