Violetta has chosen a life with Alfredo, and they enjoy their love in the country, far from society (“De’ miei bollenti spiriti”). When Alfredo finds out that this is only possible because Violetta has been selling her property, he immediately leaves for Paris to procure money. Violetta has received an invitation to a masked ball, but she no longer cares for such distractions.
While Alfredo is in Paris, his father, Giorgio Germont, visits Violetta. He demands that she separate from his son, as their relationship threatens his daughter’s impending marriage (“Pura siccome un angelo”). Over the course of their conversation, Germont comes to realize Violetta’s unselfish love. Violetta’s resistance dwindles and she finally agrees to leave Alfredo forever, asking that after her death he shall learn the truth (“Mor- rò! La mia memoria”).
Violetta accepts the invitation to the ball and writes a goodbye letter to her lover. Alfredo returns, and while he is reading the letter, his father appears to console him (“Di Provenza il mar, il suol”). But all the memories of his home and his happy family can’t prevent the furious and jealous Alfredo from seeking revenge for Violetta’s apparent betrayal.
At the masked ball, news has spread of Violetta and Alfredo’s separation. Meanwhile, Violetta and her new lover, Baron Douphol, have arrived. Alfredo and the Baron battle at the gaming table and Alfredo wins. When everybody has withdrawn, Alfredo confronts Violetta, who claims to be truly in love with the Baron. In his rage Alfredo calls the guests as witnesses and declares that he doesn’t owe Violetta anything (“Ogni suo aver tal femmina”). He throws his winnings at her. Giorgio Germont, who has witnessed the scene, rebukes his son for his behavior. The Baron challenges his rival to a duel.

Violetta is dying. Alfredo’s father has written to Violetta, informing her that his son was not injured in the duel. Full of remorse, Germont has told his son about Violetta’s sacrifice. Alfredo wants to rejoin her as soon as possible. Violetta is afraid that he might be too late (“Addio, del passato bei sogni ridenti”). The sound of rampant celebrations are heard outside. But Alfredo does arrive (“Parigi, o cara, noi lasceremo”). Violetta’s energy and exuberant joy of life return. All sorrow and suffering seem to have left her — a final illusion, before death claims her.