Signs of oestrus, including vulvar swelling and alopecia are frequently seen in ovariectomized ferrets. Between 1997 and 1999, 25 ovariectomized ferrets presented with symptoms of vulvar swelling and symmetric alopecia at the University Clinic of Companion Animals. In 18 of these animals, ovarian remnants were found. To prevent failure to remove all ovarian tissue in the ferret, thorough identification of the ovaries, which are surrounded by large fat deposits, is necessary. The incision should be long enough to allow good visualization of the surgical field.