The Wadeable Streams Assessment program focuses on the use of a consistent scientific and technical tools for evaluating ecological conditions on regional and national scales. The methods and instructions for field operations presented in this manual for surveys of wadeable streams were initially developed and tested during 5 years of pilot and demonstration projects (1993 - 1997) and modified for use in a study of streams in the Western US (2000-2002). These projects were conducted under the sponsorship of the U.S. Environmental Protection Agency and its collaborators through the Environmental Monitoring and Assessment Program (EMAP). This document describes procedures for collecting data, samples, and information about the benthic macroinvertebrate assemblage, environmental measures, or attributes of indicators of stream ecosystem condition, and were developed based on standard or accepted methods, modified as necessary to adapt them to sampling requirements for the Wadeable Streams Assessment. They are intended for use in field studies sponsored by the USEPA, or monitoring programs developed and implemented by various State and tribal agencies. In addition to methodology, additional information on data management, safety and health, and other logistical aspects is integrated into the procedures and overall operations. Procedures are described for collecting field measurement data and/or acceptable index samples for several response and stressor indicators, including water chemistry, physical habitat, and benthic macroinvertebrate assemblages. The manual describes field implementation of these methods and the logistical foundation constructed during field projects. Flowcharts and other graphic aids provide overall summaries of specific field activities required to visit a stream site and collect data for these indicators. Tables give step-by-step procedural instructions. These figures and tables can be extracted and bound separately to make a convenient quick field reference for field teams. The manual also includes example field data forms for recording measurements and observations made in the field and sample tracking information. Checklists of all supplies and equipment needed for each field task are included to help ensure that these materials are available when required.