A tentative deal also was reached with automotive supplier Delphi Corp. The agreements were announced more than three days after labor pacts expired at midnight Sunday.
GM chairman and chief executive Rick Wagoner said the agreement, which still requires approval from union members, "will allow us to work together to address what is clearly a challening set of competitors."
No details on the four-year deals were released, but UAW President Ron Gettelfinger had said they would be modeled after tentative deals reached earlier this week with DaimlerChrysler AG's Chrysler Group.
Two sources familiar with that deal said it includes a $3,000 signing bonus, a lump-sum payment in the second year and wage increases of 2 percent to 3 percent in the third and fourth years. The union also managed to avoid radical changes to its low-cost health care insurance program, said the sources, who spoke on condition of anonymity.
The UAW also reached tentative agreements with Ford Motor Co. and supplier Visteon Corp earlier this week.
"In the last five days we have successfully concluded negotiations with five of the largest manufacturers in the world," Gettelfinger said. "That's five for five."
The union and GM had negotiated "late into the night" Wednesday, GM spokesman Tom Wickham said. A union vote on the deal was expected in the next week to 10 days.
The sources said the pacts also include provisions for plant closings or sales, though GM hasn't publicly targeted any plants for closing.
Ford has said it plans to close four U.S. plants in New Jersey, Missouri, Ohio and Michigan. The company said those closings, along with some shift reductions at other plants, would affect 12,000 workers.
UAW leaders met Wednesday with union representatives of at least seven Chrysler parts plants that could be sold or closed, according to a union source who attended one of the briefings. The list includes plants in Michigan, Alabama, Indiana, Ohio and New York and affects about 12,000 workers.
GM, the world's largest automaker, has 115,000 active UAW workers and another 340,000 retirees and spouses. Delphi has 30,000 UAW workers.
Employees have reported for work as usual throughout negotiations.
Some analysts said the GM deal was probably delayed because of stumbling blocks over company-specific issues.
Delphi was spun off from GM in 1999, and the automaker remains its biggest customer. The union has said it would like GM to continue buying parts from Delphi as opposed to nonunion suppliers. At the same time, GM is under intense pressure to lower operating costs.