A nurse at the Norfolk and Norwich University Hospital is facing disciplinary action after medical notes were found in a wheelie bin.
Hospital carried out an investigation to find who was responsible
The confidential hospital records of 55 patients were found dumped in a bin on a housing estate at Bowthorpe, near Norwich, Norfolk.
The hospital said it was investigating how the files were lost in a serious breach of confidentiality.
A member of the public made the find as she emptied her bin.
A hospital spokeswoman said the matter was "a deplorable and very serious breach of patient confidentiality".
The misplaced data included the name, hospital number and brief medical details of 55 patients.
Addresses, contact details and NHS numbers were not included on the papers, she added.