[en] This report describes the results of activities conducted to assess and document the need for guidance or regulatory involvement by the Nuclear Regulatory Commission (NRC) in the development, upgrading, use and control of maintenance procedures in US nuclear power plants. Reported are the findigs of the following four activities: (1) a survey of current maintenance procedure practices in seven US nuclear power plants, (2) a review and analysis of plant administrative and maintenance procedures, (3) a survey of maintenance procedure practices in industries that share some characteristics with the nuclear industry, and (4) a review of the research pertaining to job performance aids and a brief analysis of their applicability to maintenance in nuclear power plants. Based on these findings, several recommendations for NRC action to upgrade maintenance procedure programs are offered