Valli died Saturday at age 85 and laid in state for two days, ANSA reported.
Italian President Carlo Azeglio Ciampi mourned her as "a great loss" and Rome Mayor Walter Veltroni called her "one of the most intense faces in movie history."
Valli was billed in Hollywood as "the next Garbo" and "the next Ingrid Bergman," but her thick accent kept her from getting roles so she returned to Italy where she achieved superstar status in more than 100 films.
She devoted her later years to the stage but returned to the screen in the 1970s to make three films with Bernardo Bertolucci -- "The Spider's Stratagem," "1900" and "La Luna." Her final film role was in the 2002 horror film, "Semana Santa."
She was honored for lifetime achievement at the 1991 Daviddi Donatello Awards, received a Golden Lion in Venice in 1997 for her contributions to Italian cinema and won the Vittorio De Sica prize in 2001.
She married painter, pianist and composer Oscar De Mejo in 1944 and they had two children. However, they split in 1954 amid a scandal that nearly ended her career, ANSA said.