This article is devoted to the history of one of the oldest Siberian health resorts known as "The Karachi Lake". It describes the stages of its development, the scientific component of the system of spa-and-resort therapy and medico-social rehabilitation of the patients. The detailed analysis of the mechanisms underlying the beneficial action of the natural therapeutic factors, cooperation with the leading research institutions, and the formation of the modern scientific and technical basis have strengthened the position of the resort on the market of the medical, health-promoting, and recreational services due to the development of the new activities in this field.