We report successful cases of surgical treatment for three ferrets with a tumor at the end of the tail. The tumor in each case was smooth and solid, and had a calcified shadow in the center radiographically. Case 1 was a three-year-old spayed ferret with a thumb-sized tumor at the tail tip. Three months after the first visit, the tumor was removed because it became twice as large, although it was painless and not itchy. This ferret has been in good condition for 18 months after the operation, without any signs of relapse or metastasis. Case 2 was a castrated four-year-old ferret. The tumor was thumbsized at the first visit, but the pet owner did not want the animal to have an operation. Ten months later, the tumor became as large as an egg, and it was removed successfully. Case 3, a castrated four-year-old ferret, received surgery ten days after the first visit, and a thumb-sized tumor was removed. This ferret also has been in good condition for 22 months after the operation, without relapse or metastasis. We have no information about the postoperative course of case 2, because the pet owner did not come back after surgery. Histopathologically, the tumor in each case was diagnosed as a chordoma.