DETROIT --- Ford Motor Co. workers have overwhelmingly rejected contract changes that would have allowed the automaker to cut labor costs, leaving Ford at a disadvantage to its Detroit rivals as it continues its struggle to return to profitability.

The United Auto Workers union had given local unions until Monday to complete voting. However, a person briefed on the voting said Saturday that the contract changes have been rejected by large margins. The person asked not to be named because the UAW has not announced the results.

The UAW and Ford agreed to the contract changes several weeks ago, but Ford workers needed to ratify them. Ford has 41,000 UAW-represented workers.

Two large union locals in Kentucky and Ford's home city of Dearborn, Mich., rejected the contract Friday, sealing its fate. Those unions together represent 13,000 Ford workers. Exact tallies weren't available, but at least 12 UAW locals representing about 27,500 workers so far have vetoed the deal, many overwhelmingly. Only about four locals with a total of 7,000 members favored the pact.

Ford sought the deal to bring its labor costs in line with Detroit rivals Chrysler Group LLC and General Motors Co., both of which won concessions from the union as they headed into bankruptcy protection earlier this year. Under pattern bargaining, the three automakers usually match pay, benefits and other contract provisions.

But workers weren't convinced they should make more concessions, since Ford avoided bankruptcy and is considered healthier than its rivals.

Rocky Comito, president of UAW Local 862 in Louisville, Ky., said Friday that workers felt they were being asked to sacrifice more than the company's executives. Ford CEO Alan Mulally made $17.7 million last year, although that was down 22 percent from the year before.

Ford was offering workers a $1,000 bonus if they ratified the contract. But the contract also would have frozen entry-level pay, changed some work rules and limited workers' ability to strike.

A message seeking comment was left Saturday for the UAW. Ron Gettelfinger, the UAW president, had said Friday that there would not be a revote if the contract changes failed. "We have a democratic process in place," Mr. Gettelfinger said at a community event in Detroit. "People have a right to express themselves."

Gary Chaison, a professor of labor relations at Clark University in Worcester, Mass., said the vote was a slap to UAW leadership. It's extremely rare for union members to oppose the union's recommended vote.