Abstract ISO/TR 28118:2009 establishes the performance indicators for national libraries. It is also applicable to libraries with regional tasks and without a defined population to be served, as many of their evaluation problems correspond to those of national libraries. The performance indicators are of special interest for comparison over time within the same library. Comparisons between libraries are possible, if differences in the tasks and constituencies of the libraries are taken into account. ISO/TR 28118:2009 does not include performance indicators for evaluating the outcomes or impact of library services either on individuals, on the communities that libraries serve, or on society at this time. Since this is an evolving area of performance measurement for libraries, such performance indicators can be added at a later date. ISO/TR 28118:2009 is not intended to exclude the use of any performance indicators which have not been specified herein.