The technology company's investment will see them support the team and its body, the Amateur Rowing Association (ARA), for a six-and-a-half-year period.
Siemens was one of the sponsors of London's successful Olympic bid, and the company hopes this investment will prompt other companies to sponsor Olympic sports before 2012.
Alan Wood, UK chief executive of Siemens, said: "This is about more than branding. We have a track record of introducing technology to sport and we intend to focus our efforts on helping British rowing in any way we can."
Siemens will also sponsor the August World Rowing Championships at Dorney Lake, Eton, the venue for the 2012 Olympics rowing events. It will be the first time the championship has been held in the UK for 20 years.
Wood said: "Our core business is about making things better and helping companies and communities compete and flourish in world markets: the fit with rowing is right for us."
The ARA receives lottery funding, but this is one of the biggest private sector invesments to be secured in British rowing. It will fund training of the ARA men's, women's and disabled crews.
David Tanner, manager of the GB Rowing Team and performance director of the ARA, said: "This partnership with Siemens will help us spot new talent and develop a world-beating rowing team. We are also excited at the prospect of working with some of the country's top scientists to help us stay ahead of the competition in sports science."
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