The Associated Press report said the company did not name a replacement for Donahue, 57, who was CEO of Nextel before it was acquired by Sprint last year for $35 billion, creating the nation's third-largest cellular provider with more than 40 million wireless customers and $40 billion in annual revenue.
Donahue's resignation surprised some analysts, but Sprint spokesman David Gunasegaram said there had been speculation since the two companies merged that Donahue would stay for only two years, the Associated Press report said.
Gunasegaram stressed that the resignation was voluntary and had been expected internally, the report further said.