Visitor numbers to an Oxfordshire museum tripled in the month following the introduction of free admission.
The number of people visiting the Oxfordshire Museum in Woodstock in April 2003 was up 300% on the same month in 2002.
Charges were introduced to museums across the county in the early 1990s.
The charges were taken away last month following a number of campaigns.
'Taken aback'
Oxfordshire County Council's culture boss, councillor Neil Fawcett, said: "We always knew that visitor figures would rise once charges were taken away.
"But we have been taken aback by the threefold increase.
"Many people who would not have considered visiting if they had to pay an admission charge are being tempted to drop in and browse."
The museum features collections of local history, art and archaeology, as well as a gallery exploring the county's industries from nuclear power to nanotechnology.