Paimio Sanatorium was built in 1930-1933 on the basis of architect Alvar Aalto's winning entry in an architecture competition (1928-1929). The site of the building was a sandy terrain in the middle of a pine forest, and was considered a healthy location.
The main building was placed on the highest point of the area, and oriented in a north-south direction. The functions of the building - the patient rooms, sun balconies, common rooms, maintenance and technical spaces - were each placed in their own wing. In particular, the patients' social areas and rooms were oriented in the most favourable direction with regard to light. The various wings meet at a central connecting node, where the most important internal circulation routes are located. The building is dominated by a 7-storey patient-room wing, with its connecting sun balconies facing directly southwards.
Other buildings in the hospital complex, such as the doctors' and nurses' residences, the sauna, heating plant and garage, were freely laid out within the grounds of the sanatorium. The mainly two-storey residential buildings are organised hierarchically, and represented in their time a progressive type of housing. All buildings are white-rendered, forming an impressive contrast to
the dark green fir trees of the forest landscape. The burial chapel (the so-called Rose Cellar), the water-pumping station, and the biological water purification plant were placed at the edge of the sanatorium grounds.
In the 1960s a terraced house for nurses and a garage - also designed by Aalto's office - were added to the area.
The immediate surroundings of the buildings are maintained in a park-like manner. Originally patients could take walks along a serpentine path, located south of the patient wing, which lead to a fountain. Typical for the overall character of the hospital, however, is the areas of pine forest, with an under-vegetation of blueberries and lingonberries. There are wide views over the landscape from the hospital's roof terrace (the former sun deck).