Officials at Fort Leavenworth say Bradley Manning has arrived at the U.S. Disciplinary Barracks to begin serving his 35-year prison term.
Manning had previously spent nearly two years at an adjacent prison while awaiting court-martial.
The soldier was sentenced Wednesday for sending classified government material to WikiLeaks.
Manning announced Thursday that he intends to live as a woman and go by the name Chelsea Manning. Manning asked the Army to begin hormone therapy as soon as possible.