International students pay double the $6,445 tuition of Missouri residents, and the lost revenue amounts to $14 million, according to Roger Best, the chief operating officer for the school, in Warrensburg, Mo. Dr. Best said that the university has been forced to cut instructors in computer programs, where many of the foreign students were enrolled, as well as defer maintenance and shave money from other departments, such as the campus newspaper.

Nationwide, the number of new foreign students declined an average of 7 percent this past fall, according to preliminary figures from a survey of 500 colleges by the Institute of International Education. Nearly half of the campuses surveyed reported declines.

Now that the revenue stream appears to be diminishing, the financial outlook may be dire enough to weigh down the bond ratings of some schools, making it more expensive for them to borrow money, according to Moody’s Investors Service. Last month, Moody’s changed its credit outlook for higher education to “negative” from “stable.”

“Growing uncertainty for international student enrollment stems from immigration policies that are in flux,” Moody’s said, warning that universities without global brand recognition would be hit hardest. While some flagship public and elite private colleges have been affected, the Institute of International Education said, the biggest impact will be felt by second-tier institutions.

The shift comes just as some states also are experiencing a drop in domestic students, partly the result of a decline in birthrates two decades ago. This year, the number of domestic undergraduate students dropped 224,000, or 1 percent, according to the National Student Clearinghouse Research Center.

An increasingly diverse population in that age group means that more of the students come from low-income families in which no one has ever gone to college, also presenting recruitment challenges for universities, according to Doug Shapiro, the organization’s executive research director. “Affordability issues are the biggest hurdles,” Mr. Shapiro said. “There’s only so much you can do with recruiting if the families can’t afford the tuition.”

Officials at Kansas State University in Manhattan, Kan., reported an overall enrollment decline of more than 900 students, including 159 fewer international students. One official cited a “perfect demographic storm.” Budget cuts are underway.