BACKGROUND: Since 2016 outbreaks of yellow fever are reported in Brazil. This is a risk to unvaccinated travellers in that area. CASE DESCRIPTION: In early January, an unvaccinated traveller returning from São Paulo attended our outpatient clinic complaining of symptoms later diagnosed as yellow fever. The disease manifested itself as fever, lower back pain, nausea and highly elevated liver enzymes. A yellow fever infection has multiple stages. The first stage is acute infection which merges into the second stage which is when improvement occurs. Either improvement continues or transfers into a third stage which is characterized by multi-organ failure. In this particular patient, stage three did not occur. CONCLUSION: The goal of this case report is to show that vaccination against yellow fever is the most important preventive measure when travelling to an area where the yellow fever virus is in circulation. Yellow fever should not be forgotten in the differential diagnosis of a traveller with fever