Gastrointestinal foreign bodies are reported in zoo birds, ratites, and juvenile psittacine birds; however, foreign body ingestion by adult psittacine birds is uncommon. We examined an adult umbrella cockatoo (Cacatua alba) because of a 4-month history of weight loss and intermittent, dark brown, malodorous stool. Physical examination findings were unremarkable. Results of laboratory testing revealed anemia, leukocytosis, lymphopenia, monocytosis, hypoproteinemia, and hypoalbuminemia; blood lead and zinc concentrations were not elevated. Enterococcus durans was cultured aerobically from the feces. Gas-filled, dilated intestinal loops and a gas-filled proventriculus were evident on survey radiographs. The clinical signs did not resolve with initial treatment, which included ciprofloxacin, ketoconazole, and a lactobacillus supplement. Over the next 2 months, results of blood tests revealed nonregenerative anemia, intermittent leukocytosis, monocytosis, and hypoproteinemia. Staphylococcus lugdunensis and E faecium were isolated from a crop swab and fecal samples. A barium contrast study revealed a filling defect in the area of the large intestine, whereas results of fluoroscopy were normal. The cockatoo responded poorly to further treatment, including 5 days of supportive care in the hospital, and the owners requested euthanasia. On necropsy, a string foreign body (7 cm long) was found in the proximal large intestine. The string had originated from a rope toy in the bird's cage.