Police have recovered a stolen National Health Service laptop containing names, addresses and dates of birth of 11,500 children.
The computer was one of three stolen from Nottinghamshire Teaching primary care trust on 21 March. It contained data on child patients aged between eight months and eight years.
A spokesperson for the PCT said technicians were examining the laptop to try to establish whether thieves had accessed the data.
After the theft, PCT chief executive Wendy Saviour said: "The information was protected by a password, which reduces the chances of anyone being able to see the information."
But the PCT was unable to confirm if the data was protected by any other security measures - or explain why the confidential information on thousands of children was held on the laptop in the first place. The PCT said this was a matter that was under investigation as part of an internal inquiry.
The theft from PCT offices at Sherwood Forest Hospital followed a break-in through a window.