A federal jury this afternoon acquitted multimillionaire businessman Dominic F. Antonelli Jr. and former D.C. Department of Human Resources Director Joseph P. Yeldell of bribery and conspiracy charges, dramatically reversing the fortunes of two of the most dominant figures in the District of Columbia's political and financial communities.

As U.S. District Court Judge Gerhard A. Gesell read the verdict, a cheering, backslapping group of attorneys and supporters surrounded the two men, who less than a year ago were convicted of the same charges by a federal jury in Washington.

A broad smile swept across Antonelli's usually impassive face as Gesell turned to the defendants and said, "Mr. Antonelli and Mr. Yeldell, at long last you are free to go your way." Yeldell, leaning back in his chair, remained almost immobile for several seconds before he, too, grinned.

The verdict, which came after 6 1/2 hours of jury deliberations over two days, ended nearly three years of government efforts to prove that the pair corruptly conspired in the award of a $5.6 million lease for a building owned by Antonelli.

The original guilty verdict was overturned and a new trial ordered after it was learned that a juror failed to disclose information about her contact with two of Antonelli's myriad business interests in the city. That information might have led defense attorneys to exclude her from the jury.

The trio of government prosecutors left the courtroom quickly and silently after the verdict was read at 2:20 this afternoon. Only Assistant U.S. Attorney Henry F. Schuelke III would comment. "The verdict speaks for itself," he said.

Outside the downtown courthouse, Antonelli's defense attorney, Edward Bennett Williams, said, "We cut out a lot of extraneous issues this time around, so the jury was able to focus on the real issues in the case -- intent."

John A. Shorter Jr., who represented Yeldell, credited the turn-around in the case to the revamped defense strategy -- including the decision to keep Yeldell off the witness stand -- and to the switch in the location of the trial.

"These jurors had no information, no knowledge about the case. The smartest decision we made was getting the change of venue," Shorter said as he clambered into a station wagon to return to the Barclay, the fashionable downtown hotel where the defense team had set up its headquarters.

In contrast to their handling of the first trial, defense attorneys in this case chose not to contradict the prosecution's evidence that Antonelli had given the financially troubled city official a secret $33,000 loan while simultaneously negotiating a lease with Yeldell's department.

That loan, the defense contended, was merely an act of friendship, a gesture divorced from the negotiations for the lease of Antonelli's rundown two-story office building at 60 Florida Avenue N.E.

After they had spent some time studying the numerous documents involved in the case, particularly the detailed three-count indictment, there was little disagreement among the 12 jurors, according to Leamon Monk, a 58-year-old North Philadelphia auto repairman who served on the jury.

"We couldn't call it bribery because the guy that got the loan paid it off," said Monk, referring to Antonelli's $33,000 loan to Yeldell.

Another juror, Joseph M. Daday, 61, said, "there was nothing to prove there was a conspiracy between the two defendants by the evidence presented . . . there was no proof . . . that this was bribery." Daday noted that according to testimony the "money was repaid with interest."

While Daday praised the oratorical abilities of Williams, and other jurors gave credit to all lawyers in the case, Daday said "the evidence was not enough for me and the rest of the jury members to come up with anything but a not guilty verdict."

After the initial seconds of jubilation when the verdict was read, Antonelli escaped from the embrace of defense counsel David E. Kendall and headed quietly for a telephone so he could call his wife. "Please, no comment," he said, putting up a cautionary hand as reporters approached.

His voice dropped as he said, "Just . . . I'm happy."

Moments later, a jaunty Yeldell walked out of the courthouse into a small forest of microphones and cameras. "Those three years are behind us," he said. "They've . . . taken their toll. Not only on me, but on my wife and children. It's been awful."

Asked about his plans, Yeldell said, "I haven't thought about any future plans. I just want to go home."

Shortly after his indictment on April 6, 1978, Yeldell went on paid leave from his GS-18, $47,500-a-year job as general assistant to then-mayor Walter E. Washington, the No. 3 post in the Washington administration.

Later that year, when his paid leave ran out, Yeldell took leave without pay and has remained in that status. Last month, Mayor Marion Barry granted Yeldell an extension of the leave, until the end of next month.

Jose Gutierrez, acting director of the D.C. office of Personnel, said yesterday that Yeldell still has reinstatement rights. But because he requested the leave, he has no right to sue for back pay, Gutierrez said.

"He is in effect an employe of the D.C. government who was granted leave without pay," Gutierrez said. "It's not a question of rehiring him because he was never fired."

Since earlier this year, Yeldell has worked for the Hagans Management Corp., a realty management firm owned by businessman Theodore Hagans. When Barry replaced Washington as mayor Jan. 2, he filled Yeldell's old post with Ivanhoe Donaldson.

"As far as his [Yeldell's] status with the government is concerned," Barry said yesterday, "it is a matter that he and I will be discussing in the next week or so."

During the first trial, Yeldell spent three grueling days on the stand, frequently contradicting himself under a withering cross-examiniation by assistant U.S. attorney Richard L. Beizer. The major change in the defense's pared-down case in the second trial was the decision to keep Yeldell from testifying, leaving it to Antonelli to explain the dealings between the two men.

Friends and associates of Antonelli and Yeldell said the verdict was the only one they would have believed. "Only someone who would know Mr. Antonelli and know what a fine gentlemen he is would know that those things were not ture," said Joseph H. Riley, president of National Savings and Trust Co.

Herbert Barksdale, who was one of Yeldell's chief lieutenants at the Department of Human Resources and who still works there, said he was "more than happy."

Sam Jordan, Mayor Barry's chief community troubleshooter, and a longtime Yeldell ally, almost leaped with joy when a reporter told him the news outside the District Building.

"From what you're telling me, I'm high," Jordan said ecstatically. "Especially because of what Joe has been through and what his family has been through."

The controversy spawned by the Yeldell affair created the most serious political challenge of Washington's 11 years as mayor of the nation's capital. But, Washington was terse and formal in his comments.

"The jury in Philadelphia has spoken and found them not guilty. This sustains my confidence in the American judicial system," Washington said.

Mayor Barry was almost equally brief. "The jury has spoken. Mr. Yeldell has been declared innocent and that is that," Barry said in a statement read by his press secretary.

Supporters of both men said yesterday that the change of location for the retrial was a major reason for the difference in verdicts.

"This [case] involved an important political figure at a time when we were in a political situation -- it was in the midst of the elections and a time of political upheaval," said lawyer R. Robert Linowes, an associate and friend of Antonelli. Washington lost a bid for reelection in September 1978 to Barry and former City Council chairman Sterling Tucker.

Riley also said that the newspapers were "a great deal to blame" for the furor over the case, as well as federal prosecutors with "unlimited funds to spend and accountable to no one."

The events of the past three years have irrevocably changed the fortunes of Yeldell, 47, the feisty product of an inner-city Washington neighborhood who had moved rapidly through a series of jobs as a teacher, IBM employe and executive before becoming a major force in the embryonic world of District politics in the late 1960s.

In 1971, four years after former President Lyndon B. Johnson selected him for a seat on the first D.C. City Council, Yeldell was picked to head the newly formed Department of Human Resources, a sprawling agency with a budget that had reached $400 million annually by the mid-1970s.

But the political successes of the man was one of the closest confidants of then-mayor Washington were not matched by similar success in his private financial ventures. In 1971 Yeldell founded a travel agency, Entrepreneuer Travel Associates Inc. in partnership with some old friends and college classmates.

Two years later, with the travel agency floundering, Yeldell took out a series of loans, first from the McLachlen National Bank and then from the Industrial Bank of Washington, eventually ending up $110,000 in debt to these two institutions.

In the fall of 1973, when he found himself rejected in an attempt to get more credit from the banks, Yeldell sought help from a businessman who put him in touch with Antonelli. Antonelli, now 57, already knew Yeldell and had contributed to his earlier political campaigns. A canny, publicity-shy businessman, Antonelli, in the years since World War II, parlayed a series of ventures in real estate and parking lot management into a $20 million fortune.

After meeting with Yeldell, Antonelli and John Lyon, his partner in Parking Management Inc., agreed to guarantee a $25,000 loan for Yeldell from the Madison National Bank, in which he was a major stockholder.

According to testimony by prosecution witnesses, just before the loan was finally approved in December 1973, Yeldell, in his role as DHR director, had renewed the required certificate of need for Doctors Hospital, which Antonelli helped direct and in which he had a small financial interest. The certificate allowed the hospital to continue in operation.

Prosecutors had argued to the jury that those events -- which they sarcastically referred to as a "coincidence" -- uere a prelude to the alleged conspiracy between Antonelli and Yeldell which began two years later.