Elderly blacks are three times as likely to be poor as elderly whites and more likely to live in poverty than any other major racial or ethnic group, according to a national study prepared for Congress and issued yesterday.

Elderly black women, particularly those who are single, are "clearly one of the most economically deprived groups in our society today -- about seven out of every eight are either poor or economically vulnerable," the report said.

The report was compiled for the House Select Committee on Aging by the National Caucus and Center on Black Aged Inc., a Washington-based advocacy group organized in the early 1970s to advance the cause of older blacks encountering the "double jeopardy" of age and race.

Regional and national leaders in the field of aging immediately applauded the report, which they said represents the first major effort to provide a comprehensive picture of the status of elderly blacks.

"I didn't learn anything I didn't know before," said Rep. George W. Crockett (D-Mich.), a member of the committee. "But it's one thing to know it and another to document it for others."

The report said that one in three elderly blacks now lives below the federally defined poverty level, at least in part because of inadequate income and retirement benefits when they were working. Many older black workers, according to the report, had jobs that weren't covered by Social Security or private pension plans, and others had low-paying jobs that provided only minimal retirement benefits.

Their poverty also leads elderly blacks to be among the most poorly housed in the country and makes them more likely to have health problems and run a greater risk of being crime victims, the report said.

Clavin Fields, director of the Institute of Gerontology at the University of the District of Columbia, said the findings in the report "are not new to those of us who have been in the field."

Fields said that although the District has tried to increase services, poverty among elderly blacks here has been aggravated by increases in the cost of housing and health care.

The District reaches an estimated 25,000 persons over the age of 60, most of them black residents near or below the poverty level, with services that include serving 4,000 meals a day and operating 15 senior centers and five elderly day care programs.

Sue Ward, director of the Prince George's County Department of Aging, said the report findings "seem totally accurate" based on the poverty she has seen among elderly blacks in her area. When the county recently decided to install indoor plumbing in homes without any, she said, officials found that many of the people who had been without this basic convenience were poor black women.

"Older blacks are the poorest of the poor among the elderly," said Samuel J. Simmons, president of the National Caucus and Center on Black Aged.

The study documented the impoverished status of elderly blacks with information from the 1980 census showing that 35.2 percent of blacks aged 65 or more are below the poverty line, compared with 12.8 percent of elderly whites, 14.5 percent of elderly Asians and Pacific Islanders, 25.6 percent of Hispanics and 32.1 percent of Native Americans, Eskimos and Aleuts.

The poverty group includes a single elderly person with an annual income of less than $5,156 and an elderly couple with less than $6,503, according to federal guidelines.

"Many senior citizens did not become poor until they became old," Simmons said. But many blacks, he said, have known poverty all their lives, "from the moment of conception until death. Advancing age simply intensifies their problems."