An aging lactating alpaca was presented in sternal recumbency. Although bright and alert, she did not respond to symptomatic treatment and was euthanized 5 weeks after initial presentation. Gross postmortem examination revealed purulent material in the pulmonary airways. Histologic examination of the lungs revealed an extensive pyogranulomatous pneumonia with bronchiectasis. There were abundant fungal hyphae and high numbers of associated oxalate crystals, which were presumed to have been produced by the fungus. Low numbers of yeast cells were also present. Microbiological culture of tissues on horse blood agar and Sabouraud's agar identified the fungus to be Aspergillus niger. There was also moderate growth of Candida albicans. Calcium oxalate crystals in cytologic and histologic preparations can suggest an underlying Aspergillus infection. This is the first reported veterinary case of pneumonia due to Aspergillus niger infection and the associated production of oxalate crystals.