More than 7,000 of them received letters saying their names and Social Security numbers had been stolen.
Now, there is growing concern about overall security at the university.
It was one computer that was stolen, but it contained the names and information of the 7,000 City College of New York students.
The computer was password protected, but it's out there, and that has left students and their parents wondering who stole it and what they intend to do with it.
Bianca Arroyo could not believe what she was reading.
"I called my son right away and told him something is wrong, something happened in the school, someone stole someone's computer with a database with the personal information," Arroyo said.
Arroyo got a letter on Saturday from CCNY, where her son is a junior.
"I'm worried, you know, because the situation with things happening nowadays with identity theft that later on that something could happen to my son, and now he'd have to be the one responsible for it," Arroyo said.
The letter said that if anyone had questions regarding the matter to contact an assistant vice president of the school at (212) 650-5426, but students said no one answered the number provided.
Potential victims say they are worried.
"I've gone to the school for the past two years, I don't want anyone looking at my information," said one student.
They are also now concerned about security at the school.
"Why was that all on one computer? It's a good question right?" said another student.
"This time it's the computer, but who knows what's next," another student said.
That's what Arroyo also said.
"If that can happen, anything can happen in the school," she said. "There's no security, the way it should be."
A spokesperson for the school says there is no evidence yet that anyone's personal information has been compromised.
However, the computer was only stolen a few weeks ago, so it may be too soon to tell.
The school says it is making efforts to ensure that computers that contain this kind of information are better protected in the future.