More than 35,500 people have died from coronavirus in Italy, which was one of the first countries in Europe to be hit by the pandemic.
The country, where almost 276,000 cases of the virus have been recorded, emerged from a strict two-month lockdown in early May.
The crowd was composed of anti-vaccine activists and conspiracy theorists.
“No masks, no social distancing,” one banner read.
Others were emblazoned with the slogans “Personal freedom is inviolable” and “Long live liberty”.
One protestor reportedly burned a photograph of Pope Francis with the word “Satan” and the number 666 on his head.
Demonstrators chanted “No Mask”, “Hands off the children” and “Truth”, while during the protest against the so-called “health dictatorship”, a demonstrator fainted, leading to calls from the stage asking if there was a doctor among the crowd.
Earlier in the day, Prime Minister Giuseppe Conte reacted frostily saying: “More than 274,000 ill and 35,000 dead. Full stop.”
The rally was also condemned by Rome Mayor Virginia Raggi, Lazio Governor Nicola Zingaretti, and Italian Health Minister Roberto Speranza, who stated: “Seeing a piazza of deniers sincerely makes one shudder. You don’t deny the virus, you fight it.”
With ANSA