Yellow fever (YF) is a mosquitoborne viral disease that has caused deaths in U.S. and European travelers to sub-Saharan Africa and tropical South America. Although no specific treatment exists for YF and the case-fatality rate for severe YF is approximately 20%, an effective vaccine is available. This report describes a case of fatal YF in an unvaccinated traveler who had returned from a 6-day fishing trip on the Rio Negro west of Manaus in the state of Amazonas, Brazil. Because information from some commercial outfitters and travel agents might underestimate health risks, healthcare providers and travelers should review vaccination and other traveler's health recommendations from public health agencies.