The Mayo Clinic Alix School of Medicine in Rochester, Minn., erroneously emailed 364 letters of acceptance to students seeking admission.
The school said the letters, which were emailed by mistake Feb. 13, have been withdrawn.
"Soon after the emails were sent, a technical error was discovered and the letters of acceptance were withdrawn by email," according to a statement on the school's website. "All affected applicants have been contacted by phone."
Admissions Dean J. Michael Bostwick, MD, told CNN the school makes offers to just 46 students, and the school always makes initial offers over the phone.
"We're still not clear how this happened, and we're so upset for these folks," Dr. Bostwick told CNN.
The medical school said it is continuing to investigate the issue.