Despite last-minute telephone calls from President Carter, his wife, Rosalynn, and other administration officials, the North Carolina legislature today rejected ratification of the Equal Rights Amendment for the third time in five years.

The Carters called at least five opposition senators, but the five all held firm and the Senate rejected ratification, 26 to 24.

The North Carolina House voted 61 to 55 to approve ratification last month. Since then, however, ERA opponents have mounted an aggressive campaign, lobbying regularly in the General Assembly here in Raleigh and in the home districts of the legislators.

Joining in the campaign against the ERA were former U.S. Sen. Sam J. Ervin, who chaired the Senate Watergate committee, and Phyllis Schlafly, a leader of the nationwide anti-ERA drive.

The North Carolina vote was a sharp blow to ERA proponents. Thirty-five states have ratified ERA; thirty-eight are needed. But in the last six weeks ratification drives have stalled in several states.

Proponents here vowed to try again at the next regular session of the legislature in 1979.

"It will be before the states until it passes, even if the Congress has to reenact it. It's a matter that will come about," said Rep. George W. Miller of Durham, a key leader of the pro-ERA forces.

Passed by Congress in 1971, the constitutional amendment needs ratification by three-fourths of the 50 states by March 1979, or the process must be started anew.

In 1973 the North Carolina Senate rejected ERA on the first attempt. Two years ago it was rejected by the House.

Proponents thought they had a better chance this year. Besides the President and his wife, North Carolina's governor, James B. Hunt Jr., is also an advocate. He called for ERA's ratification in his initial message to the General Assembly in January.

Basically, those legislators who were lobbied by the President and his wife cited constituent pressure back home in remaining firm against the ERA.

"My people are two to one against it," said Sen. Bobby Lee Combs, a minister and day-care operator from Hickory in the western part of the state. Combs, a Democrat, received a call from Mrs. Carter Monday night and the President Tuesday. The President told him, "The whole world will be watching North Carolina."

Combs, describing his reaction to the call, said, "I put my head down . . . and cried. It was the President." But Combs told reporters he could not change his vote because he opposed ERA during his election campaign last fall and wanted to stick by his pledge.

Besides the Carters, Commerce Secretary Juanita Kreps, formerly vice chancellor at Duke University in Durham, and Robert Lipshutz, counsel to the President, also made telephone calls urging passage of ERA.