Biological aging is characterized by the progressive deterioration of the function of all fissues and organs, leading to the loss of ability to restore homeostasis un- der stressful conditions and, consequently, to the in- creased risk of development of aging-related diseases. This phenomenon also affects the neuroendocrine function of hypothalamus-pituitary axis, as well as influ-
ences the structure and function of peripheral endocrine organs. Aging is also accompanied by changes in the number and sensitivity of receptors that may change the responsiveness of target tissues to hormones and neurotransmitters. However, it is sometimes difficult to distinguish the effects of aging per se on endocrine physiology from these caused by diseases since their signs and symptoms might overlap. In addition, signs and symptoms of endocrine disorders in the elderly can be poorly expressed and atypical (1). In this review we present basic concepts regarding pathophysiology of some endocrine dysfunctions in elderly patients, as well as brief guidelines regarding diagnosis and treat- ment of these conditions.