It is generally recognized that the inorganic phosphate ingredients in mixed feed or mineral supplements are the principal source of fluoride in the feed. Today, there are several types of feed phosphates available to the feed industry. This paper discusses how these supplemental phosphates are produced, the quantities utilized by the feed industry and what species consume them, and describes their phosphorus content, fluoride content and general cost. The phosphate industry, along with university researchers and the Association of American Feed Control Officials, set up standards for safe levels of fluoride in feed phosphates. A P toF ratio of 100:1 was adopted in 1952 for any product sold to the feed industry as "defluorinated phosphate." The phosphate industry has felt that products with this ratio are safe, and, on the basis of evidence available today, it is still felt that this is a safe level of fluoride in supplemental feed phosphates. Industry has the technology to produce feed phosphates of lower fluoride content; however, there is an increased cost in further reducing fluoride content.