During an outbreak of yellow fever (rural form of the infection) occurred recently in the State of Goiás, Brazil, a patient, with clinical manifestations suggestive of the infection, died in the University Hospital of Brasilia, DF, on the fifth day from admission. Postmortem examination revealed, microscopically, the characteristic alterations of the infection, and discovered in the lungs and hilar lymph nodes round microrganisms identified as adiaconidia of Emmonsia parva var. crescens.