Created by five watch-making cantons (Bern, Geneva, Neuchâtel, Soleure and Vaud), and by the Federation of the Swiss Watch Industry (FH), the COSC brings together a number of laboratories that were originally founded as independent institutions in the late 19th century.The first "Office for the Control of Civilian Watches" was established in Biel in 1878.
Prior to 1973, the five watch-making cantons had "official offices of control of the rate of the watches", located either within watchmaking schools or engineering schools, which evaluated the quality of horological objects according to various criteria, which often differed from one canton to another.
In the early 1970s, faced with the lack of unity in terms of approach and solidarity of the OL – among other things – and the threat to their official status, the Central Inspection Commission of the offices proposed the creation of a Commission comprising the five cantons housing the OLs, the Swiss Chamber of Watchmaking, and the FH. This resulted in the creation in 1973 in La Chaux-de-Fonds of the "Contrôle officiel suisse des chronomètres" (Swiss Official Control of Chronometers). Since then, the COSC has been a not-for-profit organisation serving Swiss watch brands.
While the five cantons retain a number of prerogatives (including a majority presence in the general assembly of the Association), the objectives of the trademarks have been achieved: identical observation conditions and the unification of tariffs. Irrespective of the quantity of timepieces submitted, and whether a brand submits 100,000 instruments to the COSC or just one, the price per instrument is the same.
Originally, the COSC operated seven OL. Over the decades, the entity has been simplified, culminating in a structure with three OL in Biel, Le Locle and Saint-Imier