Version 1.0 of the Pacific Northwest Standard Taxonomic Effort (PNW-STE) is the culmination of many years’ work and builds greatly off the 2015 preliminary version hosted at the Pacific Northwest Aquatic Monitoring Partnership web site (www.PNAMP.org). This tool standardizes the nomenclature and taxonomic targets for data generated from freshwater benthic macroinvertebrate biomonitoring (BMI) samples within the Pacific Northwest, continental USA. Described is the scope of the PNW-STE both geographically and in application, rules associated with the development and formatting of taxonomic names, suggested methods to increase harmonization and data quality, and guidelines for communication between biomonitoring project managers and laboratories contracted to perform sample analysis. This STE applies specifically to BMI samples collected from mid-order streams in the PNW with the objective of assessing the biointegrity of waterbodies. In the past several decades, this type of information has been routinely collected by all levels of government, private industry, and non-governmental organizations for multiple purposes, including regulatory (biocriteria). Standardizing laboratory protocols and data reporting is foundational for the many study and regulatory objectives this data is currently being tasked with. Though the application specifically targets the analysis of mid-order stream benthic biomonitoring samples, this STE also serves as a guidance for levels of taxonomic resolution that can be practically achieved in studies on other freshwater habitat types (e.g. lakes, rivers, headwater springs and streams, etc.), or for different sample types (e.g. drift, qualitative multi-habitat, fish gut content, food web, etc.)