In a tough economy, it's harder than ever for professionals to switch to new career fields. But take one or two years off to earn an M.B.A. and changing professions may not be too difficult.

That's what recent b-school graduates who made dramatic changes in their careers after they got their degrees tell us. You don't even have to know what you want to do when you enroll, says Chris Watkins, an Iowa high-school teacher who became a bank lending executive after completing an M.B.A.: "I was your typical kid graduating. I didn't have a master plan coming out of b-school, but I like what I do now, even though I fell into it by accident."

It's easiest, of course, to change careers when the economy is hot. Two graduates we interviewed landed their new roles during boom times. It will be harder now to switch professions because of the limp economy, says Mel Penn, president of the M.B.A. Career Services Council, a professional group, and an executive at the University of Oklahoma. However, in two years, the economy may improve enough that the M.B.A. class of 2004 will have more options.

Choosing a narrow field or location to work in are other key reasons why some b-school graduates don't succeed in making a switch, says Mr. Penn. Not securing internships or making needed contact in a new field are others, says Janie Thomas, M.B.A. director of placement at the University of Kentucky.

Mr. Penn estimates that typically only between 5% and 10% of new M.B.A.s at most have trouble changing careers for those reasons. "It's not degree-related," he says. "Changing careers is a valid reason for going to b-school, but if the employment outlook in every industry is poor, you aren't going to be able to cross into any industry."

While school officials don't know the exact percentage, most say between half and three-fourths of their students enroll in M.B.A. programs to switch careers. The Graduate Management Admission Council in McLean, Va., which polls b-school graduates nationwide, doesn't ask them if they have changed careers. But for the past three years, about three-fourths have said getting the degree has expanded their career options because they can now seek jobs in different industries or organizations. This year, about 60% said the M.B.A. increased their career options by allowing them to make a career transition.

"We tell them that wanting to get an M.B.A. to change careers is the right decision," says Jim Gray III, associate dean of marketing and communications at Duke University's Fuqua School of Business in Durham, N.C. "We call them career switchers and more, not less, are wanting to do that." He notes that most career changers enroll in the Fuqua School's full-time day program, not its part-time evening or weekend classes.

At Iowa State University's College of Business in Ames, about half of graduate business students want to make a career change of some type, says Mark Peterson, director of graduate career services. "They come back to retool to put a new spin on their careers or move in a different direction," he says. And at Northwestern's Kellogg School of Management, the "vast majority" ends up changing careers or industries after earning M.B.A.s, says a spokeswoman.

Of course, as a career-change tactic, this one isn't cheap. Tuition, room and board ranges from about $20,000 for two years at a lesser-known business school to about $100,000 at a highly ranked one. The rate of payback depends on the salary you earned when you enrolled vs. what you earn after the degree.

For those who aren't sure what career path to follow, getting an M.B.A. can help you solidify your choice. We asked a former teacher, customer-service representative and nonprofit employee how getting an M.B.A. helped them to move in new career directions. Reviewing their accounts may help you decide if b-school is a good option for you.

After getting an undergraduate degree in 1989 in environmental science at the University of California-Irvine, Melissa Lyons "dabbled in all kinds of things" for a decade, from counseling foreign students to retail sales. While working as a branch sales manager in Michigan for Enterprise Rent-a-Car Co., she realized she wanted a different role in business. "I knew I didn't want to have to depend on a commission, and I wanted more involvement in company decisions," Ms. Lyons says.

She visited professors at the University of Arkansas' Sam M. Walton College of Business in Fayetteville, near her parents' home, to discuss getting a master's degree in finance. "I told them about my personality and what I liked," says the 35-year-old. "They said an M.B.A. would be better for me and convinced me to try it."

Ms. Lyons enrolled in the college's one-year M.B.A. program in 1999 at age 32. To offset her tuition, she worked three hours a day helping to administer the school's entrepreneurial program. In 2000, she graduated with an M.B.A. in finance and marketing. By then, she knew she wanted a job that involved financial analysis and marketing. A professor suggested she investigate marketing roles at consumer products companies. She found plenty of them in nearby Bentonville, which is home to Wal-Mart Stores Inc. and a hotbed for companies seeking a bigger share of business with the world's largest retailer.

Ms. Lyons landed a position as category-products analyst with Whitehall Robbins, a pharmaceuticals maker, and a year later switched to a similar job at Del Laboratories Inc., which sells three cosmetics lines and nail-care products. Now 35, she's been promoted twice and is a category development manager. She makes upwards of $80,000 annually, almost $60,000 more a year than in her car-rental-agency job.

Ms. Lyons becomes emotional when describing her gratitude for her professors and what the degree gave her. "I wanted to get to the point where I made more money and felt successful at what I did. Three years ago, I never thought I would own a house. I've been promoted twice in this job and I just bought my second house. The M.B.A. gave me an overall view of how business should be run and how women function in that world. The professors made it easy for me. It was one of the most inspiring experiences I ever had."

Teaching high-school math for two years in Early, Iowa, after earning a mathematics degree at Iowa State was enjoyable for Mr. Watkins, but he felt constrained by the career. Further, his annual salary in 1997 for teaching and being the school's basketball, football and track coach was roughly $25,000.

"Teaching isn't as financially rewarding as other professions, and there are no advancement opportunities," he says. "If you are a really, really good teacher, in your second year you'll be paid the same as any other second-year teacher and less than a really bad teacher with 10 years' experience."

To increase his options, Mr. Watkins enrolled in the M.B.A. program at Iowa State's College of Business in 1997, graduating two years later with a specialization in finance. When interviewing for jobs, he decided to accept an offer to become a management trainee at Omaha-based Commercial Federal Bank because the bank would move him throughout its departments. However, his wife was working in Des Moines and he opted to remain there, so he became a commercial-loan underwriter instead. Three-and-a-half years later, he's the department manager.

Mr. Watkins likes his role because it involves approving large loans and allows him to meet company decision makers and analyze their businesses' future prospects. He hopes to move up in the bank by relocating to its Omaha headquarters eventually. Financially, his M.B.A. has more than repaid itself. Mr. Watkins worked as a research assistant in business school, which paid about a third of the school's $4,400 annual tuition for state residents. Now age 30, he earns close to triple his teacher's salary and is rewarded for his performance, one of his original career objectives.

Lauren Creamer earned a health-related degree in 1996 from Vassar College and then worked in an orphanage in Ecuador. She returned to the U.S. to take a variety of jobs at nonprofit organizations in the San Francisco Bay Area, including counseling runaway youths, developing programs for children with HIV and running a YWCA entrepreneur's program for teenage girls.

From the latter job, she realized that a business could support and help people in a positive way. "Working with kids transformed me in terms of how I thought about business," she says. "I knew I wanted to start a company, but I didn't know enough about the processes of business to execute the idea effectively."

She enrolled in the two-year entrepreneurship M.B.A. program at Babson College's F.W. Olin Graduate School of Business in 2000. Initially, she didn't know what type of business she wanted to start, but the Babson program helped her clarify that "kids were my passion and always would be."

She's now president and CEO of Firefly Toys Inc., which she started in Babson's incubator. A "therapeutic" toy company, Firefly makes products, such as stuffed animals or kits, to help caregivers work with children who are going through difficult life experiences. Now based in New York City, the company has about $100,000 in seed financing and services.

While Ms. Creamer expects to make money as an entrepreneur, making a difference in the world is her main motivation. She has about $35,000 in student loans to repay but says the expense is worth it. "I got a whole new set of skills I can use to start a company," she says. "The M.B.A. has paid for my freedom. Now I don't have to work for anyone else."