The University accepted 581 of the 1,815 early decision applicants to the Class of 2008, Dean of Admission Janet Rapelye said. The 32 percent acceptance rate was a nearly seven percent increase over last year's rate.
"We had a powerful early decision pool and your credentials stood out from the other files," Rapelye wrote in her letter to accepted candidates.
Though the number of students who applied early is down 25 percent from last year, the University continued its trend of filling just less than half of the entering class through early decision. Princeton had fewer early applicants than Harvard, Yale and Stanford universities, which all changed their admission system this year.
Yale, which was second-last in the number of applications received, exceeded Princeton by more than 2,000 applications, while Stanford and Harvard both received about 4,000 applications as well.
Christopher Avery, a professor at the Kennedy School of Government at Harvard University who studies the U.S. college admissions system, said Princeton's drop is to be expected.
"One of the things that we would have predicted very broadly was that Princeton would lose applicants to Yale and Stanford [both of whom adopted single-choice early action programs this year]," Avery said in a interview.
However, Avery said he does not believe the smaller number of applications is a problem for the University.
"It's understood that you're going to get less applicants than if you had an early action program. I don't think anyone would make a comparison between [early action schools and early decision schools]. It's unfair," he said.
Harvard received 47 percent fewer early applications this year and accepted roughly a quarter of applicants to its undergraduate college through its new single-choice early action program. This year's acceptance rate is the highest since 1996 and roughly eight percent higher than last year.
Harvard director of admissions Marlyn McGrath Lewis attributed the significant rise in students accepted to the drop in the number of early applicants.
"While the number of applicants declined considerably, the quality was again quite remarkable," she told the Harvard University Gazette.
The number of early applications to Stanford rose 62 percent, Stanford admissions dean Robin Mamlet reported.

Stanford, which last year had a binding early decision program similar to Princeton's, also switched to a single-choice early action program for the class of 2008. Under its new early admission program, Stanford admitted 25 percent more candidates over last year.
Though exact figures are unavailable, about 20 percent of students who applied under Stanford's early admission program were admitted.
Yale University has yet to release its early program's acceptance numbers. However, early applications to Yale are up more than 50 percent this year.
Yale, like Stanford, dropped its binding early decision program this year in favor of a single-choice early action program.
Class dynamics
Perhaps the most significant change this year for Princeton's early acceptances is the concentration of engineers. The University accepted 27 percent more applicants to the School of Engineering and Applied Science compared with the Class of 2007, Rapelye said.
Asked whether he thought accepting more engineering students indicated Princeton was losing humanities and social science applicants to other selective colleges, Avery acknowledged the possibility. However, Avery cautioned that such theories, without additional data from college admissions offices, are speculative at best.
The important question, Avery said, is whether engineers were accepted at a higher rate than humanities and social science applicants.
Rapelye could not be reached to discuss Avery's question or comment on whether the larger accepted engineers group in the early decision round may lead to a smaller accepted engineers and larger humanities and social sciences group in the regular decision round.
Women make up 46 percent of those already accepted to the Class of 2008, while men make up 54 percent. Rapelye reported that "the admitted students [for the Class of 2008] are from 40 states, plus the District of Columbia, and 30 different countries," adding that "18 percent of the admitted students are students of color."
Rapelye did not report the number of legacy applicants admitted early this year. In the past, about 15 percent of an entering class are sons or daughters of Princeton graduates.
Also unknown are the number of students whose admission decision have been deferred until the regular decision round.
New committee format
Rapelye said in an email that she does not have the final say when it comes to accepting, deferring or rejecting a particular student.
"Every file was fully evaluated by a team of readers and we used a committee format for most of the decisions," she said.
In past years, though admission officers reviewed applicant files and made recommendations, former dean of admission Fred Hargadon made the final decision on every applicant.
In her March 2003 interview with The Daily Princetonian, Rapelye had hinted that she would consider changing to a committee system. At Wellesley College, where Rapelye was previously admissions dean, students are selected for admission through a committee vote of faculty, administrators, students and admission counselors.
Rapelye says no to "YES!"
Hargadon's famous "YES!" letters are gone. Rapelye opted for a more traditional note of congratulations to this year's accepted applicants.
"Congratulations! . . . Your academic accomplishments, extracurricular achievements and strong personal qualities were deemed by the readers to be exceptional and ones we wanted here at Princeton," she wrote. "We are pleased to be sending you this good news and especially to be welcoming you to Princeton."