The Cancer Ward is a novel about a Soviet man, Oleg Kostoglotov, who is admitted to a Soviet hospital somewhere in Asia, and is treated for several months for a tumor. As Oleg communicates with his fellow patients and interacts with the physicians treating him, he learns to define himself and his future. Emerging from years of prison camps and exile, Oleg discovers he still has the capacity to love. He also learns that even a strong man as himself can be brought down by disease, and can be brought down by the overwhelming cruelty of the Soviet system.

Through a series of incidents, examples of other citizens, and conversations between the patients, the faults of the Soviet system are exposed and criticized by the author.

The story begins with Pavel, a member of the Soviet secret service, being admitted into the cancer ward, and his evaluation of each patient. The story of each patient is outlined, and their thoughts about their predicament and disease.

The doctors and nurses and orderlies of the cancer ward are also described, along with their motivations for working within the Soviet medical system. It soon becomes clear that this medical team is a mix of inept political appointees and dedicated physicians. The dedicated doctors must deal with Soviet rules and regulations, inadequate staff, antiquated equipment and the lack of updated scientific information.

The patients in the ward come and go, with some being discharged, some moving to surgery, and some dying. The men keep up a continuing conversation about life, their reading material, the government, and about the cancer itself.

Oleg and Pavel become opposite ends of each argument, and they resent each other for different reasons. Pavel sees Oleg as a barbarian, and Pavel represents the authority that has ruined Oleg's life.

Oleg questions his treatment, but Zoya and Vera both persuade him to go through each phase as prescribed. He has a physical attraction to Zoya and an emotional one with Vera, and cultivates both relationships throughout his hospital stay. Oleg's disease takes its course, with him feeling better after the x-ray treatments, then feeling very bad during the injections. When he is finally released, Oleg has been cured, but told to come back in six months.

On the day Oleg is discharged, he has invitations from both Vera and Zoya to stay with them, but chooses to visit the town and the zoo before he goes to either one of them. Oleg is giddy with freedom, love and joy. The town's banality, the blank faces of the citizens and the overwhelming choices at a market cause Oleg to feel confused and lost. He goes to the zoo, a place long discussed and described by Dyomka, to regain his feeling of joy. He is happy to see the animals until he comes to the monkey exhibition. There is a sign on one of the cages that the monkey has been injured by a careless act, and this depresses Oleg immensely.

Oleg goes to Vera's house, but she is not home. He goes to the exile office and gets his train pass so he can return to his village. He is regaining his feeling of composure and strength, and uses his prison experience to manipulate those around him so he can get a good spot on the train.

As he settles down for the two day train trip, he suddenly remembers the blinded zoo monkey and Oleg is plunged into despair.