Facing the midnight Saturday expiration of labor contracts covering 39,000 workers in nine states, including Maryland, Verizon reported little progress in the negotiations with two unions late Friday.
Members of the Communications Workers of America and the International Brotherhood of Electrical Workers have voted to go on strike if necessary over the dispute.
The contracts cover employees from Massachusetts to Virginia who work for Verizon's wireline business, which provides fixed-line phone services and FiOS Internet service.
The unions say the telecom giant is demanding that workers sharply increase their health care contributions and make concession on pensions.
In a statement Friday, Marc Reed, Verizon's chief administrative officer, called the union's counterproposal "unrealistic and out-of-touch in today's marketplace."
Verizon also said it is ready in the event of a strike, having trained non-union employees and outside business partners to ensure that service to customers is not disrupted.
CWA official Dennis Trainor said the union's members are determined. "They reject management's harsh concessionary demands."
The Associated Press contributed to this report.