The purpose of this report is to present the case of an elderly patient with perforatedchagasic megacolon associated to a gastric adenocarcinoma. Case Report: Whitewoman, 82 years old, admitted with cyanosis, anasarca, melena, abdominaldistension, and pain. The patient presented positive serology for Chagas disease.On physical examination, the patient presented poor general condition withdistended and diffusely painful abdomen, without bowel sounds. The patient diedduring the first hour after admission. The histopathological examination showedchagasic megacolon with perforation that progressed to purulent fecaloid acuteperitonitis, the latter being the immediate cause of death. An area of ischemic colitiswas observed without noticed vascular pedicle torsion as a result of volvulus. Inaddition, an ulcerated gastric adenocarcinoma was diagnosed. Conclusion: Thisseems to be one of the few reports of ischemic colitis that progressed to perforatedchagasic megacolon and acute faecal peritonitis and was associated to a gastricadenocarcinoma.O objetivo deste relato foi apresentar o caso de uma paciente com megacólon chagásico perfurado associado a colite isquêmica, que evoluiu para peritonite fecal aguda. A paciente era uma mulher branca, 82 anos, com cianose, anasarca, melena, dor, distensão abdominal e sorologia positiva para doença de Chagas. Seu estado evoluiu para o óbito e a autópsia revelou megacólon chagásico com perfuração e peritonite aguda fecaloide purulenta, sendo esta última a causa imediata do óbito. Este é, provavelmente, um dos poucos relatos de colite isquêmica, megacólon chagásico perfurado e peritonite fecal aguda associada a adenocarcinoma gástrico não diagnosticado antes do óbito
