Workers are fighting for affordable benefits, fair wages, job security and outsourcing, according to CWA.
After a one-day strike, AT&T agreed not to require technicians to perform work assignments outside of their expertise.
Landline workers in California and Nevada picketed for a day in March to protest work rules for some in-home technicians and moves to replace US call-center jobs with contractors hired overseas.
Just over half of the employees work for the company's wireless business, primarily in call centers and retail stores, and have been without a long-term contract since February.
"We have made every effort to bargain in good faith with AT&T, but have only been met with delays and excuses", said Dennis Trainor, vice president of CWA District 1.
The union represents 40,000 AT&T Mobility workers. As part of its next contract, the union wants to bar AT&T from changing its commission structure unilaterally.
Unionized workers at AT&T went on strike on Friday afternoon, signaling the end of more than four years of labor peace at the company.More news: Chaffetz to resign, raising doubts about Trump probe
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If the AT&T strike goes on for weeks at the time like the Verizon strike, it could result in a disappointing jobs report.
According to the CWA's website the union plans to picket AT&T stores around the country, including one in Austintown, two in Boardman and two in Niles on Friday, Saturday and Sunday.
In addition to the call center and retail workers, the strikers include more than 15,000 employees on the company's wireline side - which includes landlines and internet service - as well as about 2,000 employees of DirecTV, which the company acquired in 2015.
AT&T has been under pressure to control costs as its biggest business - wireless phone service - has matured and faced rising competition from Verizon, Sprint and T-Mobile.
Given the current controversy surrounding the administration, it's possible that Trump will keep his distance.
Verizon workers went on strike twice while President Obama was in office, once past year and for two weeks in August 2011.