The television commercial shows a confident, well-dressed working woman pulling out her credit card to pay for a romantic dinner with her husband.

Fifteen years ago, a woman in similar circumstances would have had a hard time obtaining a credit card in her own name or without her husband's approval.

"Yesterday's pariah is today's new market," said Emily Card, a political scientist and author who helped draft the 1974 law that prohibited lenders from discriminating on the basis of sex or marital status.

The passage of the Equal Credit Opportunity Act (ECOA) in 1974, which came at a time when women were demanding more opportunities, entering the work force in increasing numbers and beginning to penetrate the higher income professions, was one of the turning points in the changing role of women in the nation's economy.

As a result of both the law and other changes, bankers no longer can assume that all women are economically dependent on men, that they will earn too little to pay the bills, or that they will drop in and out of the labor force to marry, have children or follow their husbands across the country.

Instead, bankers must deal with a world in which half of all new marriages break up, leaving more women as heads of households.

It is also a world in which many women stay in the work force through marriage and motherhood, pursuing career tracks that take them higher up the pay ladder, and in which many women are starting their own businesses.

Some bankers, business owners, women's groups and other observers credit the ECOA with forcing changes in the way society treated women as earners and borrowers, while others believe the legislation simply reflected the changes already under way.

There is also continuing disagreement over whether women continue to face sex discrimination when seeking business loans and whether new legislation is needed to stop such treatment.

Some credit the ECOA with forcing banks to abandon outdated but lingering assumptions about women that had been used to justify practices such as canceling a woman's credit when she married, denying credit to a divorced woman, not counting the wife's income when a couple applied for a mortgage, and requesting and using information about birth control practices in evaluating credit applications.

"In 1973, it was legal and considered good business practice to discriminate against women," said Card, who worked then on the Senate Banking Committee staff, which documented the practices listed above.

"One day discrimination was thought to be good business practice, and the next minute it was taboo," Card added.

Eve R. Grover, a founder and former president of the Women's Bank of Maryland, said discrimination did exist, but the bigger problem was that "women many years ago did not have the income, they were not in the work force" and therefore had difficulties qualifying for credit.

Today, more women qualify for personal credit and face the same problems men face when trying to start up a new business, said Grover, now a vice president with First American Bank of Maryland.

"The criteria for creditworthiness have not changed," Grover said. "What has changed are the women."

Women accounted for 44 percent of the civilian labor force in 1984, up from 30 percent in 1960, according to the Department of Labor.

The portion of women in the civilian labor force, defined as employed or looking for work, grew to 54.8 percent in November from 37.6 percent in 1960.

Women accounted for 65 percent of the growth in the civilian labor force from 1960 to 1984.

Not only are more women working, but more women also are staying in the labor force rather than dropping in and out as they marry and have children, said David Riesman, a Harvard University sociologist. "The really important shift has been from 'jobs' to 'careers,' " he said.

Grover said the key to improved creditworthiness was the entrance of women into the professions.

Women now account for 25 percent of the admissions to Harvard Business School, 13 percent of the doctors in the country, 14 percent of the lawyers and one-third of law school entrants.

Women were not admitted to the full program at Harvard Business School until 1963, and made up 1.6 percent of the students in 1965.

Women accounted for 6 percent of the nation's doctors in 1963 and 2.6 percent of the lawyers in 1960.

A woman who was denied a credit card 15 years ago may today run her own business.

"Women-owned businesses are the fastest growing segment of the small-business population," according to a Small Business Administration report published in May. Women owned 26.2 percent of the non-farm, sole proprietorships in 1982, up from 22.6 percent in 1977, the report said.

In 1982, 3.1 million women owned sole proprietorships, with total revenue of $44 billion, according to the SBA.

Women have entered the work force and stayed largely for economic reasons. They have held low-paying jobs for decades, many of them because they needed the income to survive. Since the 1960s and 1970s, more women have had to go to work to support themselves and their children because of divorce, or have worked to compensate for a decline in their husbands' earning power. Since 1973, there has been a general decline in men's earnings.

One reason banks are happy now to count the wife's income on mortgage applications is because "most couples can't qualify for mortgages unless both incomes are counted," said Card, author of a book on women's credit.

Another factor was changing attitudes in the late 1960s and early 1970s, said Riesman, who noted that the women's movement was "re-energized" by the civil-rights and anti-war struggles.

Women "decided it was their turn" and started demanding better jobs, better pay and equal credit treatment, he said.

"Women have joined men in wanting the best for themselves and their children," he said.

So, in some ways, the ECOA grew out of, and then gave a push to, some of the social and economic changes under way in 1974.

The act was amended in 1976 to outlaw discrimination by race, color, religion, national origin and age in granting credit.

It is difficult to estimate how much credit women have now compared with 20 years ago, because lenders did not grant credit to women often then, and now that they do, they do not compile records on the basis of sex or marital status.

But most observers agree that most banks are now eager to extend personal credit to women -- especially through credit cards.

For the last four years, women and students have been "the biggest growth area for credit-card companies," said Spencer Nilson, publisher of The Nilson Report, a credit-card industry newsletter. Two reasons have been the saturation of the mature male market and the realization by even married "non-career women" that they should have credit in their own names "because half of them are going to get divorced," he said.

Women now hold about 29 percent of the American Express cards in circulation and account for about 37 percent of new card members, up from levels below 20 percent in the mid 1970s, said K. Shelly Porges, who served as director of consumer card marketing until July, when she became vice president for card marketing in Canada.

Women account for a growing part of a growing pie. The number of American Express cards worldwide virtually doubled in the last five years, to 21.8 million in June from 11.9 million in 1980.

American Express recognized in the late 1970s that its traditional market, the middle-aged traveling businessman, was already well-supplied with credit cards, but women presented a growth opportunity, Porges said.

In 1982, the company launched a marketing campaign explicitly directed at women.

In addition to the TV ad in which the woman buys dinner, one ad shows a woman leaving a sporting goods store with a lacrosse stick and a briefcase.Another shows a woman in a business suit cheering at a baseball game with her two daughters.

Women use the cards for the same purposes as men, primarily business travel and entertainment expenses, Porges said.

The minimum annual income for American Express personal cards is $15,000, and the average is about $25,000, she said, adding that these numbers reflect the recent emphasis on marketing to women and students.

To attract these groups, which are generally less well paid than the professional men, American Express said it has lowered its minimum income requirement, although it would not say by how much or what the previous minimums were.

Grover said the battle for equal credit "has just about been won . . . we're 90 percent there."

The problems that remain include individual violations of the ECOA and rules that exempt business lending from the act's provisions, credit experts said.

"The very overt kinds of discrimination are gone, but old attitudes die hard," said Judith E. Schaeffer, a Washington lawyer and former chairwoman of the Women's Legal Defense Fund's committee on credit discrimination.

Jo Anna Filomena, owner of the Georgetown restaurant Filomena's, agrees.

While seeking a loan in 1981 to launch her business, according to Filomena, officials at two local banks asked Filomena, who was and is unmarried, "What's going to happen to the restaurant if you meet someone and get married?"

"As if I would chuck it all and take off," she said, adding that she felt the question implied she was irresponsible or too emotional to run a business. "Would they ask a man a question like that?"

Another time she had an appointment with a local banker and found that he was running late. Rather than reschedule the meeting, he told her, "Why don't you just go out and shop a while?" she said.

She later obtained a Small Business Administration loan guarantee and a $550,000 loan from a Virginia bank. This year the restaurant expects to do about $2 million in business.

Despite Filomena's eventual success, women's groups argue that her experience demonstrates the need to legislate equal treatment in commercial lending.

The ECOA does prohibit discrimination in granting business credit, but the Federal Reserve Board has adopted rules that effectively exempt that area.

Rep. Parren J. Mitchell (D-Md.) and Rep. Corinne C. (Lindy) Boggs (D-La.) have introduced a bill that would remove those exemptions.

"It's essential to get financing. . . . Otherwise our businesses can't grow as fast as they could," said Gillian Rudd, president of the capital area chapter of the National Association of Women Business Owners. The organization has found in surveys of its members that obtaining credit is the major problem. "Legislation will help document violations [of the ECOA] and get some funding behind our businesses." CAPTION: Pictures 1 and 2, Eve R. Grover says the criteria for credit hasn't changed, the women have; Owner Jo Anne Filomena expects to do about $2 million in business this year. The Washington Post