A seven year old male castrated Pomeranian, presented to the Cornell Hospital for Animals in January 2003 with a chief complaint of bladder stones and chronic urinary tract infections. Physical exam and bloodwork were within normal limits. Ultrasound and radiographs of the urinary tract at Cornell revealed several calculi in the bladder and penile urethra. A cystotomy was performed and the stones in Tino's bladder were removed. The stones were analyzed and found to be composed of predominantly calcium oxalate. Currently, calcium oxalate is the second most common mineral type identified in canine uroliths. This seminar discusses the prevalence, etiology, pathophysiology, and diagnosis of these stones. Current treatment protocols and prevention measures including dietary recommendations will also be addressed.