This experiment was conducted to investigate the use of monoclonal mouse anti-human FSH as a primary antibody for the immunohistochemical staining on chicken adenohypophysis paraffin sections. The use of monoclonal mouse anti-human primary antibody on chicken tissues has been developed. The protocol has been modified by comparing the results of the different groups. Briefly, this present protocol suggests modification in two areas; first, the antigen retrieval step, by placing the slides into the buffered citrate in microwave oven at 700 watt for 5 min, 3 times, and antigen-antibody reactions. Secondly, the incubation with the primary antibody (dilution 1/ 100 for anti-FSH) at 37degreesC for 90 min.