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
Tony Davies was the first civilian to reach Pc Palmer after he was stabbed during the Westminster attack.
Defiant Londoners put on a show of solidarity for the victims of the Westminster terror attack at a vigil in their honour.
Weather set to improve with plenty of sunshine by Saturday