Deutsche Telekom Chief Executive Rene Obermann is stepping down at the end of next year and will be replaced by his finance chief Timotheus Hoettges.
"This is the right time to prepare to pass the baton and ensure a smooth transition," Obermann said in a statement on Thursday.
Obermann, 49, has been with Deutsche Telekom for 16 years. By late 2006, he had risen to become the youngest ever CEO of a German blue-chip, at just 43.
When he took over, Deutsche Telekom was a lumbering giant with customers leaving in droves and investors wary of its ability to deliver.
As chief executive his image has been of a low-key and somewhat uninspiring leader, eager to keep unions and politicians happy and wary of taking big strategic decisions.
He suffered a blow last year when a deal to sell Deutsche Telekom's troubled T-Mobile USA business, which has been losing market share, to AT&T collapsed.
This month, Deutsche Telekom cut dividends for the next two years by almost a third investments at home and in the United States eat away cash.
"We will invest heavily primarily in our networks in Germany, but also in those in the USA, to secure the future of our company," Hoettges said on Thursday, affirming Deutsche Telekom aims to return to revenue growth in 2014.