This report describes the pathological findings of acute gastric dilatation syndrome in New World nonhuman primates that died suddenly. The animals were kept in a Zoo and were received proper nutritional and sanitary management. The animals were submitted for necropsy, and macroscopic findings included gastric and duodenal dilation with marked mesenteric vascular congestion. Gastric and intestinal contents were sent for microbiological examination, and bacterial colonies were isolated and identified as Escherichia coli, Streptococcus sp., Salmonella sp., Staphylococcus sp., and Cronobacter sakazakii. The antibiotic sensitivity test revealed that these bacteria had different re-sistance patterns to several antibiotics. Cronobacter sakazakii was susceptible to Ampicillin and Norfloxacin and resistant to Penicillin and Clindamycin. Cronobacter sakazakii is an opportunistic pathogen in animals, frequently reported in cases of human’s enterocolitis. Acute gastric dilata-tion, previously described in Old World nonhuman primates, is a cause of sudden death in Neo-tropical primates and should be considered as a differential diagnosis in cases of sudden mortality in these species. Although its pathogenicity in primates has not been elucidated, the isolation of Cronobacter sakazakii from samples suggests its presence in the environment, emphasizing the need for reinforced hygiene measures, especially of food supplied for these animals.