From March 1996 to August 1999, 24 free-ranging European mink (Mustela lutreola) and 25 free-ranging polecats (Mustela putorius) were immobilized for clinical procedures and to place radio transmitters. Data were recorded during 14 and 12 trials, respectively. Animals received intramuscularly 10 mg/kg ketamine (KET) combined with 0.20 mg/kg medetomidine (MED), antagonized by 1.00 mg/kg atipamezole (ATI). Anesthesia times were similar between species. Induction was smooth and rapid (0.7–3.9 min); the degree of anesthesia and muscle relaxation was satisfactory in most animals. Two individuals showed signs of spontaneous recovery before injection of ATI. In other individuals, ATI was injected 28.1–54.0 min after the MED-KET injection and rapidly reversed the effects of the MED. Rectal temperature and heart and respiratory rates decreased significantly 5–25 min post MED-KET injection in both species. Rectal temperature successfully remained stable by placing animals on a warmed plastic table (37 C) during anesthesia. According to these results, this anesthetic protocol produces a safe and rapid immobilization in free-ranging European mink and polecats and is recommended for surgical procedures such as radio transmitter implantation. However caution is required as hypothermia can be severe. Body temperature must be monitored and means provided to maintain stability.