The Priory Highbank Centre in Bury has been awarded the highest level of accreditation by an independent, internationally recognised body.
The three-year accreditation from CARF confirms the centre's position as a provider of quality brain injury rehabilitation and follows a rigorous review process.
The centre provides in-patient and day patient rehabilitation services for people of all ages who have suffered a brain injury due to serious illness, an accident or surgery.
Helen Powell, hospital director at the Priory Highbank Centre, said that the accreditation reflects the "hard work and dedication" of staff.
"In a climate in which we will increasingly be required by purchasers to demonstrate the quality of our service in a more objective manner, accreditation is a valuable tool and gives us an opportunity to demonstrate that we are accountable and that we are willing to open our services up to scrutiny and comparison with an established standard," she said.
The Priory Group has built up a solid reputation for its treatment and therapy programmes for depression, addiction and eating disorders.