This paper examines changes in the liturgical and paraliturgical practices of Roman Catholics in Soviet Russia in the 1920s and 1930s. Nine documents from different archives outside Russia were first used to show changes made at the request of Russian Catholics. These documents deal with a number of disciplinary issues, such as the time for the celebration of Mass, observation of a natural fast before Mass, permission for lay people to bring Holy communion to the sick or imprisoned people. The Holy See readily relaxed canonical requirements.