Summary. Characteristics of aging as a normal physiological process are presented. The main indicators of increased the number of older population in the world as well as problems related to society and particularly to public health are listed. The difference between gerontology and geriatrics is described. Retirement is separately presented as a psychological process. Reported are the most frequent chronic diseases that may develop in older people including dementia, mental depression, and other psychological problems. The theories of aging related to organs and organic systems are described. The impor- tance of geroprophylaxis, including primary, secondary and terciary prevention for older people is particularly stressed.