Prime Minister Giorgia Meloni, Senate Speaker Ignazio La Russa, and President Sergio Mattarella attended the parade, applauding the participants as they made their way along Via dei Fori Imperiali.
The day, known as Festa della Repubblica, commemorates the 1946 referendum in which Italians voted to abolish the monarchy and establish a republic, following the collapse of Fascism.
The celebrations concluded with a flypast by the Frecce Tricolori, the Italian Air Force's aerobatic team, which released trails of green, white and red smoke over the Colosseum.