The present study was undertaken to correlate the immunohistochemical expression of Bcl-2 oncoprotein in buffalo’s adrenal gland in the young and old ages. Paraffin-embedded sections from the adrenal glands representing the young and old ages were immunostained for Bcl-2 oncoprotein. A higher percentage of Bcl-2 immunoreactivity was detected in the adrenal cortical cells of the buffaloes at young ages. The immunoreactivity was moderate in the adrenal cortical cells of the old ages. The degree of intensity was prominent in the zona reticularis than that of the other zones, while negative immunoreactivity in the cells of the adrenal medulla. In conclusion, the immunohistochemical expression of Bcl-2 oncoprotein in the young buffalo’s adrenal gland (antiapoptotic gene) was prominent than the old ages. So the incidence of apoptosis was prominent in the adrenal gland cortical cells of the old age than that the adrenal gland cortical cells of the young ages.