Suddenly Serebryakov, Sonya, Marina, and Telegin enter the drawing room. While Serebyakov complains that members of the household are missing, Sonya asks Yelena if Astrov has denied her: Yelena nods silently.

Declaring he cannot accustom himself to country life, Serebryakov invites the group to sit, insisting above all that Voynitsky must stay at the meeting. Serebryakov announces that, in light of his advancing age, the interests of Yelena and Sonya, and the impossibility of his living in the country, he plans to sell the estate and invest the proceeds to provide for their income. Voynitsky is livid, largely because Serebryakov has made no plans for his mother, Sonya, and Voynitsky himself.

Over and against Maria's deferral to Serebryakov and Telegin's comically embarrassed interventions, Voynitsky reminds the group that the estate passed from his sister to Sonya, that—in the name of his sister—he gave up his inheritance and slaved to rescue it from debt. He also reminds them how he has spent years managing the estate on a beggar's wages to provide the professor's income. Though others move to silence him, he then confronts the professor directly. After years of worshipping him, he now sees him as a fraud, a worthless and failed scholar. Voynitsky claims that Serebryakov is responsible for the waste of Voynitsky's best years.

Yelena screams she must leave immediately, and Telegin storms out. Maria continues to urge her son to listen to the professor, while Sonya huddles with Marina. Serebryakov calls Voynitsky a "nonentity" and tells him to take the estate if he wants. With resolve Voynitsky storms out, ominously warning the professor that he will remember him; Maria follows.

As Serebryakov and Yelena once again announce their intention to leave, Sonya begs her father for compassion, reminding him how she and Voynitsky lived in deprivation to send him his income. Yelena tells her husband to straighten things out, and they both go after Voynitsky. Marina attempts to console Sonya, appealing to God's mercy and promising that all will pass with "some lime tea or raspberry."

Suddenly a shot rings out off-stage. Yelena screams; Serebryakov runs in terrified, begging for help. Voynitsky and Yelena struggle in the doorway; the former frees himself and fires a second shot. After a pause, it becomes clear he has missed. Utterly dejected, Voynitsky tosses the revolver to the ground and sinks into a chair.