Nicholas Salmanovitch Rubashov
Rubashov is the main character in the novel. He is a symbol of all of the men who were executed as a result of the Moscow Show Trials, and he is also representative of the Old Bolsheviks. He is a typical "toe the party line" man who is only just now wondering why he toed it for so long. He is now experiencing what those he interrogated himself experienced; brutality, sleep deprivation and being "framed" for a crime that didn't happen and never existed.
Rubashov has the opportunity to escape execution by confessing to Ivanov, an old friend whose life he once saved, but confesses too late - after Ivanov's death - and he is executed at the end of the novel.
Prisoner 402
Prisoner 402 is Rubashov's neighbor in the adjacent cell. He is initially glad that Rubashov has been arrested because he hates Communists and is a Tsarist. He is Czech and was arrested whilst serving in the military.
Number One
This is the name given to Josef Stalin, Soviet Dictator. He is presented as a figure who rules over hi people with an iron fist and it is mandatory to have his portrait hanging in every home.
Ivanov
Ivanov is Rubashov's interrogator, but in another life they were friends. Both men have the old-style civility that both feel is sorely lacking in the new generation of soldiers. Ivanov fought alongside Rubashov in the Civil War. Rubashov once saved his life, and so he owes him a debt, which he intends to repay by getting him to confess, which will mean that he is not executed, but imprisoned in a labor camp for five years. Ivanov is killed before Rubashov's trial.
Gletkin
A young and brutal interrogator, he enjoys striking fear into the hearts of every prisoner that he interrogates. He is known for having a uniform that is so starched and stiff that it makes a noise as he moves. He is an example of the younger generation that has no civility or class.