Unions at Telecom Italia have called a strike over proposals to split the firm's fixed line and mobile businesses into two new companies.
Telecom Italia announced the possible split last week
The planned 3 October walkout and street protest comes amid fears the company's new focus on broadband and media will result in job losses.
There are also reports that the strategy change will signal the sale of its mobile business, TIM.
About half of the 85,000-strong workforce are represented by unions.
Telecom Italia's change in strategy has caused a political row, forcing an adviser to Italian Prime Minister Romano Prodi to resign.
Mr Prodi, who opposes the move, said last week that he had no prior knowledge of the firm's decision.
Yet a leaked note by his aide, Angelo Rovati, appeared to show Mr Prodi did know of the plan.
Telecom Italia's net profits fell 15.7% to 1.5bn euros ($1.78bn; £953m) in the first half of 2006.
The company bought its TIM mobile business in 2005 after previously selling it off in the 1990s. Experts suggest it could be worth up to 35bn euros (£23.7bn).
Selling TIM, the last Italian-owned mobile network, would mark a major turnaround for Telecom Italia, which has recently been integrating its mobile and fixed-line phone operations.
Separate reports have suggested that rival European telecoms firms including France Telecom, Deutsche Telekom, and Spain's Telefonica - as well as US private equity firm The Carlyle Group - could be interested in buying TIM.
Telecom Italia is Italy's largest phone company, holding almost 70% of the market, and is the leading mobile operator in Brazil as well as Italy.
It also has broadband interests in Italy, France, Germany and the Netherlands and owns a number of media interests including Telecom Italia Media - which owns MTV Italia, a news agency and TV channel La7.