The ion, oxalate, and its salt, calcium oxalate, are of special interest to scientists who study bacteria, fungi, plants, animals, and humans. Scientists from other scientific disciplines including physical chemistry, biochemistry, crystallography, membrane physiology, molecular biology and genetic engineering have had interest in oxalate and calcium oxalate. Through the ideal medium of the Gordon Research Conference, these many varied disciplines can meet with a common theme to share ideas and knowledge that potentially will be beneficial to all. The first two Gordon Conferences on Calcium Oxalate were judged extremely successful by the participants and the Gordon Conference organizers. With this background and enthusiasm the third Gordon Research Conference on Calcium Oxalate will be held June 10-14, 1991 at Plymouth State College, Plymouth, New Hampshire. Scientists from throughout the world will meet to share their knowledge including the measurement of oxalate in biological fluids and tissue; the metabolic origin and roles of oxalate in biology; oxalate transport by biological membranes; and the many processes and factors involved in the crystal formation of calcium oxalate. Scientists from the varied disciplines will be called on to present papers and discuss in open forums in the informal atmosphere of a Gordon Research Conference in these important areas of mutual interest. In addition to the oral presentations and discussions, poster sessions will be featured allowing a large number of participants, especially young investigators, to share their work with the other attendees.