ASHINGTON, Jan. 23 — The difference in managerial salaries for men and women in American industry grew from 1995 to 2000, a Congressional study has found.

During one of the nation's biggest economic booms, managerial salaries for women not only failed to catch up to those of their male counterparts, they lost ground in several industries, according to the study, which was released today.

In entertainment, communications, finance, insurance and retailing, the study said, the gap between men and women grew by as much as 21 cents for every dollar earned.

The report, by the General Accounting Office, the independent research office of Congress, looked at salaries in the 10 industries that employed the most women from 1995 through 2000. It defined a manager as any job whose description included the words administrator, director, manager or supervisor. Among other controls, the study compared salaries for full-time employees only.

The study also found that women continued to be scarce in managerial ranks. Over all, women make up roughly half the work force but only 12 percent of corporate officers.

"While there has been overall progress for women, they are stalling or sliding back when they reach management," said Representative Carolyn B. Maloney, Democrat of Manhattan, who commissioned the study.

Mothers lost the most ground, according to the report.

"The widest gap was between parents," who were managers, said Martha Farnsworth Riche, an economist and former director of the Census Bureau who vetted the study for the accounting office. "Over all, women are equal to men up to about 33 years of age and then they steadily lose."

Dr. Riche noted that the dropoff probably occurred because women climbing the ranks of management at that age were most likely to begin raising children. Once they started families, mothers who were managers could count on earning 66 percent of what fathers who were managers were paid, she said.

The study found that 60 percent of women who were managers did not have children, having either forsaken or deferred motherhood or waited until their children were grown before taking on management responsibilities.

The figure for men was the reverse; 60 percent were fathers while filling management positions.

Some lawmakers said that the salary discrepancy could have a significant impact on families as the country endures a recession. Women now provide at least half of the income for more than two- thirds of American families.

"This is no longer a women's issue but a family issue," said Representative John D. Dingell, Democrat of Michigan. He said he would call for hearings to review the study's findings.

The study focused on the 10 industries that employ the most women. Three of those industries — medicine, education and public administration — narrowed the gap between salaries. Among education managers, for example, women earned 91 cents for every dollar earned by a man in 2000, up from 86 cents in 1995.

But among managers in the entertainment industry, women earned 62 cents, down from 83 cents in 1995; among managers in the communications industry, women earned 73 cents, down from 86 cents in 1995.

Some skeptics, like Randel Johnson at the United States Chamber of Commerce, doubted the results of the study would hold up under scrutiny. He said any number of reasons could explain why women's management salaries might be less than those of men.

"I doubt they have the same seniority as men," said Mr. Johnson.

But even if the findings proved accurate and women were the victims of discrimination, he said, there was no reason to hold hearings or change laws.

"If the reason for this apparent wage discrepancy is discrimination, then the law already provides for a remedy," said Mr. Johnson.

Martha Burk, chairwoman of the National Council of Women's Organizations, said most companies were not required to reveal salaries. Among managers, she said, most women were unaware they were paid less than male colleagues. If they found a difference, she added, they were reluctant to spend years suing their employers.