Following a review of the hands-off doctrine, which held that the courts are powerless to intervene in internal prison affairs, and the emergence of prisoner rights, prison discipline prior to judicial intervention in 1970 is described. Early, landmark U.S. Supreme Court decisions in Goldberg v. Kelly and Morrissey v. Brewer concerned administrative due process and exerted substantial influence over Wolff v. McDonnell. In this case, the Supreme Court provided an interpretation of the elements of due process required during prison disciplinary hearings. In a New Jersey Supreme Court decision, Avant v. Clifford, the mandated due-process protections exceeded those in Wolff. The impact of these two decisions is illustrated in a case study of disciplinary procedures at Rahway State Prison. In conjunction with the Rahway data, a review of the sociological and legal literature indicates that procedural due process protections in Wolff and subsequent case law has resulted in disciplinary practices becoming more systematic, formal, rational, and legal in structure. Factors which have blunted the overall impact of due process are considered. Procedural due process entitlement and impact theories are examined as applied by the Supreme Court in Meachum v. Fano, Montany v. Haymes, Wright v. Enomoto, and Hewitt v. Helms. The implications of these decisions for correctional policies regarding the use of administrative, as opposed to disciplinary, segregation are explored. Footnotes are provided.