Trouble that broke out on a wing at Oakwood prison, near Wolverhampton, has now been resolved, private security firm G4S has said.
It said it would be "inappropriate" to give further details of the incident, which lasted for more than five hours.
Police and internal investigations would now take place, the firm added.
The prison, in Featherstone, which has a mixture of category C and D prisoners, was the scene of a number of rooftop protests last year.
A G4S spokesman said: "This incident was resolved successfully at 2.10am. Police and internal investigations will now take place.
"It would be inappropriate to comment further until these have been completed."
The company earlier said the situation had been "contained" and it was applying "standard procedures" to manage the problem, which included bringing in extra staff.
A spokesman for Staffordshire Police said the force had offered support and assistance to G4S.
In October, an inspectors' report said the prison was failing to tackle drugs, which inmates said were easier to obtain than soap. At the time, G4S said it had already taken steps to address the problems.
The privately run prison opened in April 2012.
At first it held 1,605 category C male prisoners, but it later re-categorised 256 places for category D prisoners, who are eligible for release on temporary licences.
The prison was built next to the existing HMP Featherstone and HMP Brinsford.
Category C prisoners are classed as those who cannot be trusted in open conditions but are not considered to have the ability or resources to make a determined escape attempt.
Category D prisoners are considered to be reasonably trusted to serve their sentences in open conditions.