"I would like to announce that I am planning to visit the sanctuary in Cagliari. Almost certainly this will happen in September," Francis said at a general audience in St Peter's Square.
This would be the Argentine pope's first long trip within Italy and only his second confirmed voyage for the year after he attends World Youth Day celebrations in Rio de Janeiro in Brazil.
"There is a fraternity between Buenos Aires and Cagliari because of a history going back to the foundation of Buenos Aires" in the 16th century, the pope told tens of thousands of pilgrims.
The city's founder Pedro de Mendoza in 1536 devoted Buenos Aires to Our Lady of Bonaria — the Madonna of the shrine in Cagliari.
"This is your Madonna," the pope said.
The 76-year-old pope, formerly the archbishop of Buenos Aires Jorge Bergoglio, is the son of an emigrant from Piedmont in northern Italy.