The first United Nations Congress on the Prevention of Crime and the Treatment of Offenders adopted the rules, and the Economic and Social Council approved them in 1957. In May 1980, 36 nations returned survey questionnaires. The responses provided further confirmation of the considerable influence of the rules on national legislation or regulations. The great majority of the responding countries replied that both the prevailing prison laws and the administrative regulations, though often not yet completely incorporating the rules, have taken into account their content, so as to fully comply with them. Some countries indicated that their prison laws had already been established when the rules were adopted and that the rules had influenced later changes in practice. A few noted that no specific enactments had been made in response to the rules since the existing statutory or administrative provisions applicable to penal establishments already embodied the principles contained in the rules. In addition, considerable efforts seem to have been made to disseminate the rules in the official languages of the various countries, and most respondents reported that the rules were available to both prisoners and prison staff. Generally, the rules are included in programs for staff training. Recommendations on open correctional facilities have been used to a more limited extent. Responses regarding specific rules are listed in a data table and discussed in the text. Additional information from the survey regarding new measures and experiments in corrections and suggestions for the effective implementation of the rules is also presented. Procedures for the effective implementation of the rules, as drafted in the Committee on Crime Prevention and Control, are appended. Footnotes are included.