Three-quarters of all African Americans and other minorities serving in uniform complain that they have experienced racially offensive behavior, and less than half expressed confidence that complaints of discrimination are thoroughly investigated, according to the largest survey of racial attitudes ever conducted within the armed forces.

On a broad array of questions, whites and minorities offered drastically different perceptions of racial and ethnic relations within the military. While whites generally took positive views of the situation on bases and ships, blacks, Hispanics, Asians and Native Americans consistently expressed more negative assessments.

Overall, the reports of offensive encounters were highest in the lower pay grades. For example, 85 percent of Hispanics in junior enlisted ranks reported experiencing such incidents. But the experience of racial hostility also carried into the senior ranks, with 71 percent of black officers saying they had experienced an offensive encounter with another service member, compared with 46 percent of white officers.

The congressionally mandated survey of more than 40,000 service members was concluded in February 1997, but its release has been repeatedly delayed as top Pentagon officials debated how the results should be portrayed, according to a senior defense official. The military has often strove to project an image of itself as more effective than society as a whole in taming bias and guaranteeing equal opportunity. Through the survey, however, service members rendered a mixed verdict.

Nearly 20 percent of blacks and 13 percent of Hispanics in uniform reported that they had been given inferior assignments or evaluations because of racial bias. Only 4 percent of whites reported such treatment.

Meanwhile, individuals of different groups said they felt comfortable socializing and establishing friendships with each other. Service members of all groups also believed that race relations were better in the military than in the civilian world.

For example, nearly half of all Hispanic service members said race relations in the military had improved over the past five years, while only a third offered that optimistic assessment about the nation as a whole. And although large numbers of minority service members reported offensive encounters--such as insensitive or harassing language--in the previous year, only a small percentage said they had been subject to threats or physical harm.

"There are positive things going on in the U.S. military, which is not to say that we do not have problems," said William E. Leftwich III, deputy assistant secretary of defense for equal opportunity. "Our insistence on self-examination will bring about the institutional health we need."

As a result of the survey's findings, senior officials said the individual services are considering changes in training and orientation programs for new recruits and in procedures for handling complaints of offensive encounters.

Formal release of the survey, which was conducted by the Defense Manpower Data Center, is now expected as early as today. An executive summary of the 300-page report was provided to The Washington Post yesterday by defense officials.

Defense officials argued that the very different perceptions of race relations reported by whites and minorities simply mirror attitudes in society as a whole. And surveys of the overall population back up that contention.

A 1997 Gallup Poll, for example, found that three out of four white Americans said blacks in their community were treated the same as whites, a sentiment shared by half of all African Americans. A Washington Post-ABC News poll released the same year found that 44 percent of blacks, but only 17 percent of whites, believe blacks face "a lot" of discrimination in America.

Given the gulf in perceptions of race relations that exists in the larger society, several analysts said, the findings of the military survey were hardly shocking.

"I'm not surprised by these findings. The military is a microcosm of the larger society," said Wade Henderson, executive director of the Leadership Conference on Civil Rights. "In many ways, it reflects the subtle and deeper problems of race found in American life. Unfortunately, even in the relatively closed society of the military, a zero-tolerance policy against racial discrimination is difficult to enforce."

Margaret C. Simms, vice president for research at the Joint Center for Political and Economic Studies, a Washington-based research center that focuses on African American issues, agreed that the findings of the military survey reflected the racial and ethnic problems of society as a whole.

"The individuals who serve in the military come from the larger society," Simms said. "They do not enter the military completely devoid of preconceived notions about people. In some sense, it may be too big a burden to place on the military to correct for all that may have been encountered prior to entry into the military."

In the past, however, the military has not been content to be the same as society as a whole, at least where racial issues are concerned. It has sought to be in the vanguard of positive developments. While the survey shows that service members share attitudes found throughout American life, defense officials argue that the military is still ahead of the curve.

"I don't think you will find another major institution that is as willing to examine itself as carefully as we have and to work as hard as we have to understand how our people feel," said an official who helped conduct the survey.

Little significant difference in reports of offensive behavior was found from one branch of the armed forces to another, although the Air Force--which has a lower proportion of minorities in its ranks than the other services--reported fewer racial incidents.

The survey revealed that a considerable amount of racial and ethnic friction is associated with the military hierarchy. Most service members reported that the offender in a racial incident held a superior rank, and about 80 percent of the minorities who experienced such incidents said they did not bother to report them. The two most common reasons cited for not reporting racial incidents were a belief that nothing would be done or that the incident was not important enough to report.

Most minority service members said they believed their immediate superiors would make an "honest and reasonable" effort to halt discrimination and harassment, but that confidence declined when members were asked about the military more broadly. For example, slightly less than half of all blacks were prepared to say that senior leaders would make such efforts.