The idea to introduce a fee to enter the building, one of the few ancient Roman sites that is currently free, met with controversy when it was first mooted by Culture Minister Dario Franceschini in January to help cover the monument's high running costs.
But the minister confirmed on Thursday that the plan is on track and an entrance fee of “just a few euros” would be in place by early next year.
“We just have to work out where to put the ticket office,” he said.
Reports in the Italian press said the ticket price would be €3.
Some seven million people visit the monument, built over 2,000 years ago under the orders of Emperor Hadrian, each year.
The Pantheon, which started out as a pagan temple, is one of the best preserved ancient Roman monuments, mainly because it was turned into a church in 609 AD.
One of the building’s most intriguing features is the oculus, a 30ft opening built into the dome which illuminates the entrance with a beam of natural light. The dome was the largest in the world until the 15th century, and is still the biggest unreinforced concrete dome ever constructed.
The building contains the tombs of Victor Emmanuel II, the first king of united Italy, his successor, Umberto I, and the Renaissance artist and architect, Raphael.