German industrial and engineering conglomerate Siemens is to withdraw entirely from the nuclear industry.
The move is a response to the Fukushima nuclear disaster in Japan in March, chief executive Peter Loescher said.
He told Spiegel magazine it was the firm's answer to "the clear positioning of German society and politics for a pullout from nuclear energy".
"The chapter for us is closed," he said, announcing that the firm will no longer build nuclear power stations.
A long-planned joint venture with Russian nuclear firm Rosatom will also be cancelled, although Mr Loescher said he would still seek to work with their partner "in other fields".
Siemens was responsible for building all 17 of Germany's existing nuclear power plants.
But more recently, the firm has limited itself to providing the non-nuclear parts of plants being built by other firms, including current projects in China and Finland.
The latest decision appears to imply a step back from building "conventional islands" - the non-nuclear plant in nuclear power stations - an area in which Siemens has remained active.
However, Mr Loescher also said Siemens would continue to make components, such as steam turbines, that are used in the conventional power industry, but can also be used in nuclear plants.
He also gave his backing to the German government's planned switch to renewable energy sources, calling it a "project of the century" and claiming Berlin's target of reaching 35% renewable energy by 2020 was achievable.
The German chancellor, Angela Merkel, announced at the end of May that all of the country's 17 nuclear reactors would be shut down by 2022.
Before the Fukushima disaster, nuclear power accounted for 23% of electricity production in Germany.
The German government's decision marked a complete U-turn by the chancellor, who only in September 2010 had announced that the life of existing nuclear plants would be extended by an average of 12 years.
Siemen's move, announced on Sunday, is also a turnaround.
In 2009, the firm withdrew from an eight-year-old nuclear joint venture with French energy firm Areva, shortly before announcing its new deal with Rosatom.
"In view of global climate change and the increasing power demand worldwide, for us nuclear energy remains an essential part of a sustainable energy mix," Mr Loescher had said at the time.