Siemens & Halske (S&H) was incorporated in 1897, and then merged parts of its activities with Schuckert & Co., Nuremberg in 1903 to become Siemens-Schuckert.
In 1907 Siemens (Siemens & Halske and Siemens-Schuckert) had 34,324 employees and was the seventh-largest company in the German empire by number of employees. (see List of German companies by employees in 1907)
In 1919, S&H and two other companies jointly formed the Osram lightbulb company. A Japanese subsidiary was established in 1923.
During the 1920s and 1930s, S&H started to manufacture radios, television sets, and electron microscopes.
In 1932, Reiniger, Gebbert & Schall (Erlangen), Phönix AG (Rudolstadt) and Siemens-Reiniger-Veifa mbH (Berlin) merged to form the Siemens-Reiniger-Werke AG (SRW), the third of the so-called parent companies that merged in 1966 to form the present-day Siemens AG.
In the 1930s Siemens constructed the Ardnacrusha Hydro Power station on the River Shannon in the then Irish Free State, and it was a world first for its design. The company is remembered for its desire to raise the wages of its under-paid workers only to be overruled by the Cumann na nGaedheal government.