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
A man caught swearing at a speed camera has been jailed for perverting the course of justice after trying to dodge 69 speeding charges
Tom Hiddleston can count the royals among his legions of fans - as the Duchess of Cornwall revealed they were "gripped" by The Night Manager
MPs say the results show that Jeremy Corbyn's brand of socialism isn't working - but he has done well enough to stave off a coup.