Drift control agents are often used in pesticide drift management. Their effect is usually intended to be through increasing the droplet size produced in an application by reducing the evaporation rate of droplets and/ or other mechanisms, such as active ingredient encapsulation, or electrostatic charging. Such effects can be measured; however, standard techniques and guidelines are not currently available for many of these assessments specifically for drift control agents. The need for standard guidelines has given rise to the formation of a new task group within the American Society for Testing and Materials (ASTM). This task group falls under the jurisdiction of ASTM Subcommittee E35.22, Pesticide Application and Formulation Systems. The present paper presents a review of the main mechanisms by which drift control agents may operate, and lists the standards and test guidelines that are currently available for assessing some of these mechanisms. This review is intended to serve as a starting point for the task group to define its mission statement, purpose and scope; and to identify current resources that are available for describing drift control agents, while showing the needs for additional resources.