Calcium oxalate (CaOx) is the most common urinary stone in cats. This disease is associated with dysuria, hematuria, and life-threatening urinary tract obstruction. Stone removal is the treatment of choice; however, many recur. A prerequisite for urolith formation is urine over-saturation with calcium and oxalate. Therefore, reducing urine concentrations of these stone components are essential to prevent reformation. Enteric colonization of oxalate degrading bacteria (ODB) is correlated with the absence of hyperoxaluria and/or CaOx formation in humans and rats. ODB can prevent enteric absorption of oxalate and increase the fecal excretion of endogenously produced oxalate, thus reducing oxalate levels in urine and preventing urolith formation. The role of oxalate degrading bacteria in cats with CaOx urolithiasis is unknown. We hypothesize that decreased colonization of the intestine with ODB is a risk factor for feline CaOx urolith recurrence. This study will determine the types and prevalence of ODB in the intestinal tract of cats with and without CaOx uroliths. It is expected that the prevalence of the ODB in the intestine of cats with CaOx will be lower than in clinically healthy cats. The results of this study will provide new insights into the pathogenesis and novel therapeutic targets such as probiotics for CaOx urolithiasis prevention in cats.