Weill Cornell Medical College of Cornell University yesterday received $400 million in major gifts from a group of philanthropists to advance the school’s research and educational programs.

The largest gift came from the chairman emeritus of Citigroup, Sanford Weill, and his wife, Joan, who pledged $250 million to the medical school that bears their name. They also pledged $50 million to the university for genomics and interdisciplinary research.

The couple’s combined gift, believed to be the largest single donation to any medical school, is their third major donation to the Upper East Side institution.

“It’s like finding a good stock,” Mr. Weill joked while announcing the most recent donation. “If you find a good one, you should keep on buying it. This is a good one.”

The $400 million announced yesterday brings the Weill Cornell school to the halfway mark in the $1.3 billion capital campaign it launched in October. The campaign’s major objectives include recruitment of scientists and students, expansion of research and technology, and increased collaboration with Cornell University’s facilities in Ithaca, N.Y.

Other donations announced yesterday included $50 million from Corinne and Maurice Greenberg and the Starr Foundation, as well as $100 million from an anonymous donor.

“This is the type of day that the dean of a medical college dreams about,” Weill Cornell’s dean, Antonio Grotto, said. “By the time this campaign is finished, we will have tripled the research space in the medical college,” he said.

Introduced to sustained applause, Mr. Weill praised the school’s campus in Qatar, and choked up when discussing the importance of advancing health care in developing countries. “I apologize for being a little emotional,” he said, “But I really, really believe in this.”

“I think that medical research needs a lot of philanthropic help, that we can’t just rely on the government” and the National Institutes of Health to fund the research, he said.