The chairman of state-owned Telecom Egypt, Akil Beshir, will step down on 1 October after serving 12 years in his position, the company said on Tuesday.
No replacement was announced, but the Egyptian telecoms ministry, which appoints senior figures to the firm, is thought to have compiled a shortlist of candidates.
Landline monopoly TE says it is the largest provider of fixed-line services in the Middle East and Africa with more than 7.6 million subscribers.
A statement from Egypt's Minister of Communications and IT, Hany Mahmoud, praised Beshir's "powerful legacy" and the "lasting impression" he made on the company and the Egyptian telecoms industry in general.
But a representative of TE workers, many of whom have held sporadic protests against alleged corruption in the firm, claimed their industrial action was the true reason for Beshir's resignation.
"He did not resign -- he was toppled," Mohamed Helmy, head of TE's independent syndicate, told Ahram Online. "This was because of the wave of outrage against him in the company."
In mid-August, TE replaced its controversial chief executive Tarek Aboualam with Mohamed El-Nawawy, to roars of disapproval from workers who considered El-Nawawy too closely connected to former management.
Workers also at the time expressed disapproval at reports that Beshir would embark on a new three-year term as chairman.
On-off protests by Telecom Egypt workers in the wake of ex-president Hosni Mubarak's resignation have been accompanied by a sizeable drop in the company's profits.
The company last month reported a 25 per cent fall in its second-quarter net income, pushed lower by a 7.9 per cent fall in revenues and employee demands for higher pay.
Net income was LE613 million ($100.87 million), down from LE813 million in the second quarter of 2011.