A two-and-a-half year old male castrated ferret presented to Cornell University Hospital for Animals Emergency Service for urinary obstruction. Referring DVM radiographs revealed a large cystolith along with numerous smaller stones obstructing the urethra. Multiple attempts to place a urinary catheter were unsuccessful. As such, the ferret was referred to CUHA. The patient was quiet but alert and responsive upon presentation.. He was sedated and the bladder was copiously lavaged with sterile saline after the placement of a 3.5fr urinary catheter. The patient was taken to surgery and a cystotomy was performed. Repeated retrograde hydopulsion was unsuccessful at dislodging two stones in the urethra. Subsequently, a urethrotomy was performed. The urinary catheter was in place for 48 hours and the ferret was discharged 72 hours post urethrotomy. The stones were analyzed by the Minnesota Urolith Center and revealed to be 100% cysteine composition.