The Columbia University College of Physicians and Surgeons is one of the top medical schools in the country, and also among the most expensive. Tuition for one year is $59,364. Add in fees and living expenses, and the total is about $90,000 per year for four years.

But while some medical students now take on crippling debt to attend, a new endowment funded by one of the school’s most successful alumni is intended to eliminate the need for student loans for all of its future medical students, the school announced Monday night.

Dr. P. Roy Vagelos, 88, the former chairman of Merck & Co., and his wife, Diana, are donating $250 million to the school, $150 million of which will fund an endowment that the school projects will ultimately enable it to underwrite its student financial aid. Those students with the greatest financial need would receive full-tuition scholarships, while others would get only grants, not loans, to make up their need, the school said.

With the gift, which is in addition to some $60 million already donated by the couple, the medical school will be officially renamed the Columbia University Roy and Diana Vagelos College of Physicians and Surgeons, the president of Columbia, Lee C. Bollinger, announced on Monday evening.