Money troubles interfere with the academic performance of about one-third of all college students, and a similar number of students regularly skip buying required academic materials because of the costs, according to a survey released on Thursday.

In an era of stagnant incomes and rising tuition and student debt, the burden of college costs on families and former students is well documented. But the new findings, from the National Survey of Student Engagement, show that financial worries are a major source of stress for undergraduates while they are still in school.

About three-fifths of students surveyed reported that they often worry about having enough money to cover ordinary costs, and students who spend the most hours at paying jobs are, not surprisingly, those feeling the most financial stress. Among those who work more than 20 hours a week, about three-fifths said that their jobs got in the way of school work.

“For far too many students, this is a real obstacle to achievement,” said Alexander C. McCormick, director of the survey, which included 285,000 students at 577 four-year colleges and universities in the United States and Canada.