A statement posted on the government's website Wednesday says doctors in Brazil who are treating Lugo say the first session will be Thursday.
Dr. Yana Novis of Sao Paulo's Hospital Sirio Libanes says the remaining five sessions will be spaced out with one every three weeks.
The official website says Lugo will be able to carry out his normal presidential duties but will rest a day after each chemotherapy treatment.
The 59-year-old leader was diagnosed with non-Hodgkin's lymphoma last week. Harvard University researchers found that his cancer is of a low malignancy.
(This version CORRECTS that Lugo's chemotherapy sessions will be once every three weeks instead of once every five weeks.)