A four-year-old parrot (thought to be a Maximilian's parrot, Pionus maximiliani maximiliani) was submitted for clinical examination because of lethargy and bloody droppings. Subsequently the bird died, and tissues were submitted for histopathologic study. Death was attributed to an undetermined bacterial septicemia based on the finding of diffuse pyogranulomatous hepatitis and splenitis. During the last 3 weeks before death, the hock joint and metatarsal region of both legs became swollen. The swellings in the legs were the result of large, cystic lesions that released numerous nematodes (8 to 24 mm long) when incised (Fig. 1). About 20 nematodes were removed from cysts associated with the left hock joint. The nematodes were in several separate cysts, which were closely associated with the joint capsule or with adjacent tendon sheaths. Within each cyst the nematodes formed a tangled, coiled mass. In addition to the cysts around the hock joints, both legs had additional nematode-bearing cysts associated with the flexor tendons along the metatarsus and in the foot pad (Fig. 2). The parasites were identified as Pelecitus calamiformis (Schneider 1866), an aproctid filarioid (1). Radiographic and histopathologic examination failed to reveal changes in the osseous tissue, using sections stained by hematoxylin and eosin. Microscopic evaluation of the verminous cysts showed that the nematodes occurred both inside tendon sheaths and in subcutaneous cysts in the neighborhood of tendons (Figs. 3,