A 7-yr-old male Major Mitchell's cockatoo (Lophochroa leadbeateri) presented with a recent history of lethargy and anorexia. Physical examination revealed poor body condition and cloacal prolapse. Abnormalities on serum chemistry included severe hyperuricemia and hyperphosphatemia with a low calcium-to-phosphorus ratio. Symptomatic treatment was initiated including intravenous fluids and antibiotics. The bird continued to decline and died within a few days. Visceral gout and renal and cloacal pathology were observed on gross necropsy. Histopathology revealed chronic inflammation within the kidney, ureter, and cloaca in association with protozoal organisms and an invasive cloacal adenocarcinoma tumor. The location and morphology was consistent with Cryptosporidium sp., confirmed by immunohistochemistry and molecular testing. Direct sequencing identified Cryptosporidium avian genotype V. To the author's knowledge, this is the first reported infection of Cryptosporidium avian genotype V associated with clinical disease in birds and the first renal Cryptosporidium infection in a psittacine.