Yolk coelomitis is a major cause of death in captive sexually mature female Fiji Island banded iguanas (Brachylophus fasciatus) maintained by the Zoological Society of San Diego. The medical records, breeding histories, and pathology archival materials from this group were reviewed to study this health problem. From 1987 through 2004, deaths of nine of 21 adult females were due to yolk coelomitis. Most iguanas had a history of reproduction-related problems, which included reproductive failure, episodes of lethargy associated with ovarian activity, folliculostasis, ovostasis, and behavioral abnormalities. Most affected iguanas either were found dead or presented moribund and subsequently died or were euthanized. Clinical signs were nonspecific and included lethargy, cutaneous discoloration, and coelomic effusion. Yolk leakage in most cases was associated with the presence of large vitellogenic follicles undergoing atresia and resulted in coelomitis characterized by florid mesothelial proliferation.