African Americans still make up nearly a quarter of the overall Army, where, historically, blacks enlisted in strong numbers to take advantage of economic and social opportunities not available elsewhere.

But the drop in new recruits from that ethnic demographic means the Army has to make up ground elsewhere. Hispanics have increased from 10.4 percent of new recruits in 2000 to 13 percent in 2004; whites went from 61 percent in 2000 to 65 percent in 2004; and Asians or Pacific Islanders made up less than 1 percent of new soldiers in 2000 but nearly 5 percent in 2004.

Army studies and experts have concluded that part of the decline in African American numbers is the unpopularity of the war in Iraq among blacks, combined with realities that officials say make recruiting tougher among all groups: the virtual guarantee of long deployments overseas, and widely publicized casualties.

A study of recruiting trends prepared for the Army last August found that "more African Americans identify having to fight for a cause they don't support" as a reason they are not interested in enlisting, while, for all groups, "fear of death or injury is the major barrier to joining the military today."

"I suspect that one major factor is the war in Iraq, which is regarded differently in the black community than in the white community," said Edwin Dorn, a professor of public affairs at the University of Texas at Austin and former undersecretary of defense for personnel and readiness. "Whites strongly supported the invasion; blacks did not. It follows that the number of young whites enlisting would go up, while the numbers of young blacks enlisting would go down."

With polls showing that a majority of Americans consider the Iraq invasion a mistake, Dorn predicted trouble ahead for the Army: "This will have an effect on white enlistments in the coming months."

Douglas Smith, spokesman for the U.S. Army Recruiting Command, said yesterday that Army officials are concerned about the declining numbers, especially because African Americans historically have accounted for nearly a quarter of recruits. He said the Army is boosting cash and scholarship bonuses for enlistment and sending out flocks of new recruiters.

"We have to be very upfront about it: It is a very difficult recruiting environment because it is the first time since we've been an all-volunteer Army with this long a military engagement," Smith said. "I think it's fair to say we're concerned about it. We're concerned that we've seen a change. We're trying to get our arms around it." The decline in African American recruiting numbers was reported last week in Military Update, a syndicated column.

Military scholars said the decline was not all that surprising, in part because African Americans' propensity to join the military has been dropping over the past decade. That had led some experts to predict that the percentage of black recruits would edge ever closer to their representation in the overall population -- 12.3 percent in the 2000 census.

David R. Segal, director of the Center for Research on Military Organization at the University of Maryland, said there are a number of societal factors merging simultaneously, including an improving economy, more jobs, increasing college enrollment and the fear of getting killed on the battlefield.

"I think it's bad for the Army in the long run because it makes their recruiting more difficult as they had become dependent on the overrepresentation of African Americans," Segal said. But, he said, "it's good for the military in the long run to have it more representative of the population. African Americans are simply finding alternatives other than the military for their post-high-school trajectories."

Sgt. First Class Christopher Narvaez, 33, has been recruiting in the South Side Chicago neighborhood of Hyde Park for more than four years, encouraging young men and women from his hometown to join the Army. He said that recruiting in the predominantly black neighborhood has always been a challenge, but that the past few months have been even more difficult.

In past years, Narvaez's goal has been five recruits each month. Now, with the Army looking to increase in size and provide troops for war, his mission has nearly doubled to nine each month. Last month, he snagged four.

"Lately, I've been looking at the economy for the area," Narvaez said. "The unemployment rate dropped, and that's made it kind of difficult. It's good for the city, but it made a big challenge for recruiting. People are choosing to do other things."

According to an Army advertising study by the research firm Millward Brown last year, women were less likely to join in part because they are finding service less important to their lives and seeing combat as a deterrent.

"Over time, females are seeing less benefits to joining the Army and more barriers, particularly combat-related reasons," the study said. Female soldiers are generally excluded from front-line combat units, but in Iraq distinctions between front-line and support duty have blurred. Women have frequently participated in combat in Iraq, and 33 have died there.

The Millward Brown study also found that, among all groups, objections to the war, casualties and media coverage of negative events such as the Abu Ghraib prison scandal all took a toll: "Reasons for not considering military service are increasingly based on objections to the Iraq situation and aversion to the military."