The present report was conceived as a technical document in an effort to achieve international consensus on release criteria for the decommissioning of nuclear facilities. It provides an overview of all the factors to be considered in the development, planning and implementation of a monitoring programme to assure regulatory compliance with criteria for unrestricted release of materials, buildings and sites from decommissioning. Contents: 1. Introduction; 2. Purpose and scope; 3. Release criteria; 4. Common practices of unrestricted release; 5. Factors to be considered in determining a monitoring programme; 6. Instruments and methods; 7. Final survey; 8. Quality assurance and documentation; 9. Cost of monitoring for compliance; References; Appendix: Statistical considerations of the critical level and the detection unit.