Vice President Nangolo Mumba will take over presidential duties until Geingob's return on February 2.
Namibia's President Hage Geingob will travel to the United States on Wednesday to undergo cancer treatment, the presidency has announced.
A regular medical check-up earlier this month revealed the 82-year old head of state had cancer, his office said last week, without giving details about his condition.
The president has accepted an offer by scientists and medical professionals in Los Angeles, California, to undergo novel therapy to deal with the cancerous cells, the presidency said in a statement on Wednesday.
As prime minister in 2014, Geingob told the public that he had survived prostate cancer. He became president the following year.
Vice President Nangolo Mumba would take over presidential duties until Geingob's return on February 2, his office added.
The country is due to hold presidential and parliamentary elections at the end of 2024.