This year, women make up 48.2 percent of the pool--the highest percentage ever.

Fitzsimmons said that the number of international applicants is also up by 8.2 percent, and African-American applicants are up 8.6 percent.

"The Undergraduate Minority Recruiting program has been very helpful to our diversity numbers--not just this year and last year, but over a very long period of time," Fitzsimmons said. "Essentially what you're doing is building a relationship with schools, counselors, families."

Continuing a decade-long trend, more Harvard applicants expressed interest in engineering, computer science, mathematics and the physical sciences than last year, though interest in the biological sciences showed a slight decline.

"If you go back several decades, you'll see the majority of students interested in majoring in the social sciences or humanities," Fitzsimmons said. "In the last 10 years, we've seen closer to a 50-50 split, and more recently we've seen closer to 55 percent in the sciences."

He said that while Harvard tends to be stereotyped as dominated by the social sciences and humanities, the school is a leader in recruiting science students, even measured against competitors like MIT.

"Since the 1970s, we have quite consciously positioned ourselves to compete against anybody in the science fields," Fitzsimmons said. "That's part of the reason why the numbers have gone up over time."