The article examines the impact of the theological views of the American Protestant denominations representatives on the formation of theoretical and methodological foundations of the American prison systems. The U. S.A. is considered to be the «pioneers» in the realization of prison reforms in the nineteenth century. Actually it was in America that the first progressive penitentiary systems were arranged: Pennsylvanian and Auburn systems. The elements of American prison systems were later borrowed by European and Russian penal reformers. A characteristic feature of the initial phase of penitentiary reforms in the USA was a strong influence of the Protestant religious views.