Technical groups worldwide have been actively developing specifications and requirements for biodegradable hydraulic fluids for mobile applications. These groups have recognized that an industry-wide specification is necessary due to the increase in environmental awareness in the agriculture, construction, forestry, and mining industries, and to the increasing number of local regulations primarily throughout Europe. Caterpillar has responded to this need by publishing a requirement, Caterpillar BF-1, that may be used by Caterpillar dealers, customers, and industry to help select high-performance biodegradable hydraulic fluids. This requirement was written with the input of several organizations that are known to be involved with the development of similar types of specifications and requirements. The list of organizations consulted during this work included the VDMA, UBA, ISO, ASTM, CETOP, and BFPA, as well as several universities world-wide, oil companies, pump manufacturers, and others who are know to have specific interest in the performance and environmental aspects of biodegradable fluids.The Authors of this paper will share the requirements of the BF-1 document and discuss the choices of parameters and test methods. Items that require future development will also be discussed.