In the 1921 season on the waters of Iron in the summer are 8 sanatoria for 1166 beds, the treatment adopted in 1751, among them many children. Defined in the following year and the main profile resort treatment at the suggestion of Dr. VV. Vladimir. This is a disease of stomach, liver, urogenital organs. There are new resorts Zheleznovodsk "Mountain Air", "Oak Grove", sanatorium Central Railway Trade Unions, "Drummer", 42 sanatorium them.

Heroes Magnitogorsk Complex. Stalin and others. In 1940, 16 health centers to treat 14 sites in 2187 thousand 620 people. Since the beginning of World War II civilian travelers are replaced by wounded soldiers and commanders of the Red Army. By August 1941 it was deployed at seven hospitals in 3000 beds. On August 9, 1942 and January 1943 and Zheleznovodsk survived the German occupation. It was destroyed by 980-bed sanatorium and balneohozyaystvo.

But in April 1943, the resort again begins to take on treatment of the wounded. After the war, restored health resort activity, and in 1950, 12 health centers in 1320 for treatment beds was 19.6 thousand people. In 1970, the Government of the RSFSR adopted a long-term plan of development of the resort town of Zheleznovodsk in the next 20-25 years, and in 1972 City Council Zheleznovodsk City Council of People's Deputies approved the draft detailed plan of the central part of the resort. There are new and resorts, comfortable housing at existing resorts. In 1979, the the results of the All-Union population census in the city of Zheleznovodsk 41.2 thousand people lived.