St George's Healthcare NHS Trust has been given a clean bill of health by regulators.
The Care Quality Commission (CQC) ranked the trust in band six which reflects the hospitals at least risk, following an inspection in September giving an award of outstanding.
It is a marked improvement since the last CQC inspection of St George's Hospital in January this year.
The hospital was issued a warning after it failed to meet six of eight national standards measured during the inspection.
A report found the hospital posed just two risks and one elevated risk, out of a possible 168 measures, including the incidence of MRSA, potential under-reporting of patient safety incidents resulting in death or severe harm and an elevated risk of whistle blowing.
Under the new ranking system inspectors analysed if services were safe, caring, effective, well-led and responsive to people's needs.
Care was rated as either outstanding, good, requiring improvement or inadequate.
Miles Scott, chief executive of St George’s Healthcare NHS Trust, said: "This is great recognition for the hard work of our staff and that we will use the forthcoming inspection as a focus for further improvement."
A larger inspection of the hospital is now scheduled to help decide whether it can be granted foundation status.
Expert teams, including professional and clinical staff, will rate the trust and South West London and St George’s Mental Health NHS Trust in the next round of inspections.
If granted the trust will be given more independence to develop services and greater financial freedom.