Goose astrovirus is a novel and distinct astrovirus that causes fatal visceral gout in 4- to 21-day-old goslings. Goose parvovirus is the etiologic agent of Derzsy disease, an acute, contagious, and fatal disease that affects mainly young goslings. This paper describes the clinical signs and gross and histopathologic features of co-infection with astrovirus and goose parvovirus. Clinical signs and history included increased mortality, depression, anorexia, enteritis, joint swelling, and paralysis. Postmortem examination showed a considerable amount of urate covering the internal organs, especially the heart, liver, and kidney. Some goslings had swollen duodenum and ileum. Histologic lesions in the kidney, liver, spleen, lung, proventriculus, and brain included hemorrhage, congestion, edema, cell necrosis, inflammatory cell infiltration, and an eosinophilic protein-like substance in renal tubules. The extensive infiltration of heterophil myelocytes into the kidney, spleen, liver, lung, bursa of Fabricius, and pancreas is a new finding.