A 28-year-old female Andean condor (Vultur gryphus) housed in an outside exhibit at the National Aviary in Pittsburgh, PA, began showing signs of weakness. Toxicosis with an anticoagulant rodenticide was suspected because its mate had died 1 day earlier from possible brodifacoum poisoning. A rapid decline in the packed cell volume, despite vitamin K₁ treatment, necessitated a blood transfusion with blood from bald eagles (Haliaeetus leucocephalus) and Steller's sea eagles (Haliaeetus pelagicus). Supportive therapy after transfusion included vitamin K₁ (5 mg/kg IM q12h) as well as enrofloxacin, vitamin B complex, selenium and vitamin E, and subcutaneous fluids as needed. After a 39-day treatment period, a tapering dosage of vitamin K₁ was initiated, and treatment ended after 17 weeks. However, 2 weeks later, the bird suffered from a potential relapse. It was successfully treated with a repeat tapering vitamin K₁ regimen lasting a total of 4 months.