STUK was established in 1958. To begin with, STUK operated under the Medical Administration as the Department of Radiation Physics with the task of inspecting radiation sources used in hospitals.

As more knowledge was gained and the use of radiation and radioactive substances increased, STUK was assigned new tasks along the way. Today, STUK is a full-service expert organization in radiation and nuclear safety.

Monitoring nuclear safety was assigned to STUK at the end of the 1960s. At that time, STUK became an independent safety authority called the Radiation Safety Institute, operating under the Ministry of Social Affairs and Health.

In 1984, the name was changed to the Radiation and Nuclear Safety Authority. The new Finnish name was abbreviated as STUK, which is also the name by which the organization is known abroad.

Increase in STUK’s tasks
1958	Regulating of the use of radiation
1960	Nationwide monitoring of radiation
1965	Natural radiation
1968	Regulation of nuclear safety
1970	Radiobiology
1977	Non-ionizing radiation (NIR)
1992	Co-operation in neighbouring regions
1999	CTBT/National information center CTBT = Comprehensive Nuclear-Test-Ban Treaty