Student applications to law schools are down sharply this year, as college seniors grow leery of a degree that promises certain debt and uncertain job prospects.

The number of law-school applicants this year is down 11.5% from a year ago to 66,876, according to the Law School Admission Council Inc. The figure, which is a tally of applications for the fall 2011 class, is the lowest since 2001 at this stage of the process. The Council estimates that the application process is 86% complete, based on historical patterns.

Law school's high cost is a reason a degree may not pay off, a report warns. Above, Boston College graduates. Getty Images

Prospective law students increasingly are aware of the grim job market for lawyers and the challenges they would face in paying off law-school loans, college career advisers said. Corporate law firms, long the employer of choice for many graduates, have cut back on hiring in recent years, and most firms haven't raised salaries for starting lawyers.

A law degree can offer ample financial rewards for a select few. Some partners at corporate law firms now bill north of $1,000 an hour and earn more than $2 million annually. But to get to those exalted heights, they have to ace law school, land one of the dwindling number of jobs at a corporate firm, and then perform years of often grueling grunt work to make partner. It's far from a sure-fire bet.

Even the American Bar Association has seen fit to drive home the risks of law school. "The rising cost of a legal education and the realities of the legal job market mean that going to law school may not pay off," the ABA said in a 2009 report, which noted that the average law student could expect to graduate with more than $100,000 in school debt.

"I'm hearing from the students I work with that they are concerned about the value of a law degree," said Tim Stiles, a career adviser at the University of North Carolina. Students, he said, often tell him they have read press accounts about the difficulty of finding law jobs.

Some students are starting to feel they don't need an advanced degree to improve their career opportunities, college advisers said.

Business-school applications for the fall 2011 class have not been tallied yet by the Graduate Management Admission Council. But last year, the average number of applications to full-time graduate programs declined 1.8%, the Council said, the first decline since 2005.

"When the economy first went down, students saw law school as a way to dodge the work force," said Ryan Heitkamp, a pre-law adviser at Ohio State University. "The news has gotten out that law school is not necessarily a safe backup plan."

At Fordham University School of Law in New York, applications this year are down 15%, and those applying "appear to have analyzed the investment in law school closely and are serious about pursuing a career in law," said Carrie Johnson, a school spokeswoman.

Kent Syverud, dean of the Washington University School of Law in St. Louis, where applications this year declined more than 11%, said it was a good thing prospective students now were more "clear eyed" about the risks and rewards of a law degree.

"The froth in the applicant pool—those who were just going to law school because they didn't know what else to do and everyone told them it was a safe bet—is pretty well gone," he said.

Write to Nathan Koppel at nathan.koppel@wsj.com