Ketamine hydrochloride was administered intramuscularly to 171 individual animals of five carnivore species. The drug was used in doses which resulted in a range of effects from simple immobilization to a surgical plane of anesthesia during which minor operations were conducted. The drug was found to have a wide margin of safety, was easily administered by syringe, and took effect rapidly. Undesirable side effects of excessive salivation and maintenance of muscle tone were readily controlled by combining ketamine hydrochloride with other drugs.