The company has sponsored a team since 1991. Recently known as T-Mobile, it was considered one of the top teams on the ProTour.
"We arrived at this decision to separate our brand from further exposure from doping in sport and cycling specifically," Deutsche Telekom said in a statement.
Former T-Mobile rider Patrik Sinkewitz said doping occurred at team, both before and after Jan Ullrich was a member of the team.
Deutsche Telekom only recently agreed to honor its sponsorship contract until 2010, but reserved the right to terminate it at any time.
"This was a difficult decision given our long history of support for professional cycling and the efforts of Bob Stapleton in managing the team in 2007," said Hamid Akhavan, a Telekom board member and chief executive officer of T-Mobile International.
"We have an obligation to our employees, customers and shareholders to focus our attention and resources on our core businesses," Akhavan added. "We have worked very hard with the current team management to promote a clean cycling sport but we reached the decision to continue our efforts to rid all sports of doping by applying our resources in other directions."
Akhavan said said the company's decision was not based on any disagreement with team management.
Stapleton said he hoped the team would continue to compete despite the loss of sponsorship.
"We hope to go forward independently with the team to achieve our goals of continued competitive success and being a leader in anti-doping efforts in professional cycling," Stapleton said.