Abstract: The adrenal glands of six individuals of the Chinese river dolphin (Lipotes texillifer) were investigated. The histological structure of adrenal glands of Lipotes was found similar to that of other small whales, but the zona glomerulosa of this fresh water species is thicker than that of its marine allies. The ratio for weight of adrenal to body is 0.25 g/Kg, and the volumetric ratio for adrenal cortex to medulla is 6.59. In four individuals, the average ratio for weight of adrenal gland to thyroid gland is 1.04. The morphological changes of adrenal glands with age, the lactation and some physiological processes in relation to natural and artificial ecological conditions were discussed. The epithelial cyst found in adrenal gland of a dolphin from natural environment is also dealt with in detail.