This guidance document presents a framework for developing and implementing technically defensible Monitoring Plans for hazardous waste sites. In support of the One Hazardous Waste Cleanup Program, this document was written in direct response to, and for, site managers who are legally responsible for managing removal and remedial site activities. It is intended for use at hazardous waste sites that have completed site characterization, risk assessment, and remedy selection and are in the process of implementing a removal action or site mitigation. This guidance presents a six-step framework for developing and documenting a Monitoring Plan that will support management decisions. The framework includes the identification of monitoring objectives and development of monitoring hypotheses to focus the monitoring program, and the development of decision rules (exit criteria) that include action levels and alternative actions for terminating or continuing the site activity and/or its monitoring program. The purposes of this guidance are to provide a framework for the development and implementation of scientifically defensible Monitoring Plans; facilitate consistency of monitoring across U.S. Environmental Protection Agency (U.S. EPA or the Agency) regions and programs; and establish procedures for identifying decision criteria prior to data collection. The policies and procedures described in this document are intended solely as guidance.