Approximately 200 laboratories comprise the Soil Testing Industry in the US and Canada. These laboratories provide soil testing services to growers in order to assist with fertility and lime management of the soil for crop production. This information is also included as part of nutrient management plans and for decision making with regard to manure utilization and application. Soil testing laboratories utilize a variety of QA/QC protocols as part of their programs. One important component is the participation in outside proficiency testing programs. Several proficiency programs exist in the US and Canada, ranging from statewide/provincial programs to national and international programs. Participation in some programs is voluntary while others are mandated by law for laboratories desiring to work in specific areas. The criteria and basis of programs vary from program to program and have changed over the years. A historical overview of the Soil Testing Industry and the role of proficiency testing programs will be presented.