After the October Revolution of 1917, the Bolsheviks restructured Russia's legal system, assigning the central role in targeting their enemies to revolutionary tribunals. Within months, however, this 'revolutionary justice' was marginalized in favour of the secret police (Cheka) and a policy of terror. This article utilizes the archives of three tribunals, contemporary writings, newspapers and memoirs to examine the tribunals' investigations and trials, and their impact. It argues that the relative failure of tribunals paved the way for the terror that engulfed Russia by autumn 1918 and laid the foundations of the repressive Soviet state.