In northern Burkina Faso's Ouahigouya district 366,052 people will be vaccinated against the disease after the two confirmed yellow fever cases, the World Health Organization said in a statement.
The first case involved a seven-month-old infant who recovered from the disease, while the second case was a six-year-old boy who died two days later.
"Both cases were reported by the yellow fever surveillance system and presented with symptoms of fever and jaundice," it said.
The two cases were confirmed as yellow fever on October 3, the WHO said.
Earlier, the WHO said authorities in the Central African Republic were planning to vaccinate nearly 200,000 people against yellow fever after a case was confirmed in the La Lobaye district.
A viral disease that causes fever, muscle aches, loss of appetite and nausea, yellow fever is transmitted by infected mosquitoes. It is found only in parts of South America and Africa.