The ultrastructure of adrenal gland of guinea fowl was recorded by using scanning and transmission electron microscopy. The parenchyma of adrenal gland constituted mainly of three components, namely cortical or interrenal tissue, medullary or chromaffin tissue and vascular sinusoids. Four types of cells viz., type-I, II, III and IV were identified in adrenal cortex by transmission electron microscopy. In scanning electron microscopy the cortical cells showed blebs, cords, globules and cord like aggregates on their surface. In transmission electron microscopical observation, three types of cells were identified in medullary tissue of adrenal gland viz., Adrenaline cells, nor adrenaline cells and stellate shaped satellite cells. In scanning electron microscopical observation, the medullary cells were granular filamentous structure and showed prominent microvillus like projection on their surface.