As part of the collaborative efforts and goals of managing zoo-housed Goeldi's monkeys, or callimicos (Callimico goeldii), a retrospective review of gross and histopathological postmortem examination reports submitted to the International Studbook Coordinator was carried out by veterinary representatives of the Species Survival Plan to investigate disease trends. A total of 1,887 postmortem reports (1965–2018) collected from more than 150 institutions were reviewed. Histologic findings from 862 postmortem reports and primary causes of mortality were compiled to determine the most common findings. Within the study population, 419 individuals (48.6%) were male, 383 (44.4%) female, and the remaining 60 (7%) of undetermined sex. The primary lesion at death in adults was chronic renal disease. The other prevalent lesions included cardiac disease, myelolipomas, enteritis, colitis, and hepatitis. In Great Britain and mainland Europe, Yersinia spp. infection had significantly higher prevalence than in North American callimico populations. Multiple lesions affecting more than one organ system were identified in many animals of this study population. Results also showed that for adult callimicos in zoological institutions in North America, Europe, and Great Britain, life span has been increasing over the last 50 yr.