It's emerged that some 2,500 supporters of college's Educational Trust have been told that their personal information was sent out by mistake.
The list in question contained names, mobile phone numbers and postal and email addresses.
In a letter seen by the Herald, DCU bosses apologise and confirm that the office of the Data Protection Commissioner has been notified.
"On behalf of the DCU Educational Trust, we apologise for this human error. We have acted on this error immediately, notifying the Irish Data Protection Commissioner as well as Dr Declan Raftery, the Chief Operations Officer at Dublin City University," the letter said.
Human error is cited as the cause of the blunder -- which was carried out by officials in the college's Educational Trust.
The college wrote to those affected within days and attempted to assure them that their information will not be used inappropriately by the recipients.
"The individuals who received this information are members of the larger DCU community and any further or inappropriate use of the information is therefore unlikely," the letter states.
It continues: "We can assure you that on the direction of the Office of the Data Protection Commissioner, we have taken all appropriate steps to address this situation. The DCU Educational Trust is a professional institution that takes these errors seriously and measures have been put in place to ensure that such an error does not occur in the future."
The DCU Educational Trust was set up in 1988 in an effort to generate private sector investment for the university.
The body has generated tens of millions of euro in funds that has gone into areas such as campus development.
A DCU spokesperson was unavailable for comment when contacted by the Herald.