Myelolipomas are mesenchymal tumors composed of adipose and hematopoietic tissue. They have been reported in many species, including domestic dogs and cats, birds, mustelids, wild felids, and nonhuman primates. Myelolipomas in Callitrichidae have been reported at postmortem examination and rarely antemortem. Multiple cases of hepatic myelolipomas associated with morbidity in Chicago Zoological Society's collection of Goeldi's monkeys (Callimico goeldii) prompted a global retrospective study to determine the prevalence and investigate factors associated with this condition. A total of 842 postmortem examination reports (1965–2013) collected from 133 captive collections were reviewed. Myelolipomas were reported in 17.2% (n = 145) of animals, with significantly more female cases than male (P = 0.023). There was a significantly older mean age at death in affected animals (134 months) compared to unaffected animals (79 months) (P < 0.0001). Myelolipomas were diagnosed in the liver in all affected animals, and rarely in the adrenal or spleen. One in five (22.1%) affected Callimico had notable morbidity associated with this disease, which is markedly different from the primarily benign reports in other species. To identify disease, prevent morbidity from hepatic myelolipoma, and improve care of Callimico species in zoological collections, new Species Survival Plan (SSP) medical management recommendations include incorporating abdominal ultrasonographic examination during routine physical examinations in addition to previously recommended hematological and serum biochemical evaluations. Future studies are merited to examine the prevalence, risk factors, health effects, and treatment options of myelolipoma in living collections.