The clinical, gross morphological and histological characteristics of bilateral ovarian papillary cystadenocarcinomas in an adult female green iguana (Iguana iguana) are documented in this report. Histologically, the tumour consisted of an invasive mass of small glandular structures, irregular arboriform papillae and cystic structures arising from the ovarian surface epithelium. Metastatic implants were extensively disseminated along the serosa of the coelomic viscera, mesentery and fat bodies. Tumour morphology and metastatic behaviour indicated a close resemblance to cystadenocarcinoma in other species. Primary ovarian neoplasia is rare in reptiles; documented cases include tumours arising from surface epithelium, germ cells and sex cord stroma.