Performance measurement at the University of South Africa (Unisa) library is integrated in its planning and review procedures and is continuously adapted and improved. This paper traces the development of performance measurement at Unisa over more than a decade. Performance measurement provides an indication of how good or bad the library is doing in relation to its goals and objectives and highlights problem areas to be addressed. Advantages of performance measurement at Unisa include the six-monthly planning cycle, which encourages the staff to focus on key performance areas; and the gradual development of the system, which has resulted in general agreement on all the objectives. Disadvantages to performance measurement include its time consuming nature; and the focus on the core business of the library and resultant overemphasis on operational goals. A recent strategic planning initiative and library restructuring resulted in a new performance review and planning approach with a more client oriented focus. Performance measures must be operationally significant, simple, meaningful, and must try to measure only things that are measurable. Performance measurement at Unisa has proven its value in the planning process and has assisted in improving and maintaining library service levels. The time and resources devoted to performance measure are regarded as an essential investment. Appendices include: library goals, objectives, standards, and achievements over time; reasons for performance failure (1994); interlending performance measurement and objectives (1990-1994); performance review and management planning report for the Document Delivery Division (August 1995); and performance indicators for the library and its individual divisions. A brief discussion with the author is provided. (SWC)