Cyber attackers have accessed eBay customers' names and contact details, the company said in a statement.
eBay said: "The database, which was compromised between late February and early March, included eBay customers’ name, encrypted password, email address, physical address, phone number and date of birth.
"However, the database did not contain financial information or other confidential personal information."
The online auction site said evidence of the hack was first detected about two weeks ago, but it was now making the announcement after "extensive forensics".
More top news
Health experts warn that overcooking foods such as toast, roast potatoes, chips and vegetables can lead to cancer - so what do they advise?
Police caught more than 40 drivers an hour using their mobile phones behind the wheel, in a crackdown on distraction driving.
Nicola Adams has left the world class performance programme and will be making an announcement about her future plans very soon.