OVERALL SUMMARY The prevalence of both obesity and kidney stone disease has been steadily increasing in the U.S. over the past several decades. Calcium oxalate stones are the most common type, including within the obese cohort. There is mounting evidence that obesity is associated with increased urinary oxalate excretion, an important risk factor for calcium oxalate stone formation. To address this issue, we have established a research center that was given the acronym COOKS (Center for research on Obesity and Oxalate Kidney Stones). This Center provides a platform for novel scientific research and the infrastructure for education and dissemination of information. The research project will focus on defining the reasons for the increased urinary oxalate excretion in obese calcium oxalate stone formers. This will be accomplished by establishing a multi-institutional, synergistic, interdisciplinary group, including scientists with unique backgrounds in kidney stone research, obesity, nutrition, and renal and gastrointestinal physiology. The scientific research project will examine the influence of gastrointestinal and renal oxalate handling, and endogenous oxalate synthesis on urinary oxalate excretion in normal BMI and obese adult calcium oxalate kidney stone formers. Both established and novel techniques will be utilized. Established techniques will include extended dietary studies where levels of oxalate, calcium and other nutrients are tightly controlled. Novel techniques will involve metabolic labelling to follow oxalate handling and synthesis, and state of the art imaging techniques. The administrative core will provide oversight of research and educational activities of COOKS. It will also be responsible for financial management, maintenance of collaborations, and communication with other pertinent NIDDK-sponsored centers and program officials. The education enrichment program will continue to be broad based. The established website will be expanded and linked to both UAB and the University of Texas Southwestern. This website will promote educational events and disseminate information to the Urologic community, other pertinent investigators and the public. The data generated should increase our understanding of the relationships between obesity and urinary oxalate, the factors involved, and serve as a platform to develop novel therapies for calcium oxalate kidney stone prevention in obese individuals.