The CQC has been inspecting St Andrews Hospital in Northampton.
It has decided that one of it's services is so poor that if it doesn't get better they will close it down.
The CQC said that the service for young people was badly led and wasn't always as safe as it should be.
Most of the people who are at St Andrews Hospital are sent there by the NHS.
NHS England has said that if things don't get better it will stop paying for people to be treated at St Andrews Hospital