The US Army private accused of leaking classified documents to Wikileaks has chosen not to enter a plea at the start of his court martial.
The 24-year-old was read the 22 charges against him at a hearing at Fort Meade, Maryland.
If found guilty of leaking and "aiding the enemy" he could face a life term.
Pte Manning, who was first arrested in May 2010, appeared for a pre-trial hearing in December, following which a court martial was recommended.
Thursday's arraignment hearing offered the defendant his first opportunity to state his case personally.
As well as deferring a plea, he also passed on the opportunity to decide whether to be tried by a military jury or a single judge.
When asked if he understood his rights to counsel, Pte Manning told the judge: "Yes, your honour."
He spoke several times, giving brief replies to questions from lawyers and the judge.
Another procedural hearing has been set for 15 March.
Defence lawyer David Coombs has asked that the court martial begin in June, but prosecutors want an August start date.
Mr Coombs says his client will have spent more than 800 days in jail by August.
During his pre-trial hearing in December, defence lawyers argued that Pte Manning was a troubled young man with gender identity issues.
They suggested he should not have been sent to Iraq, where he served as an intelligence analyst with access to classified material.
Pte Manning is alleged to have been the source of a series of high-profile stories that saw Wikileaks rise to global fame.
After a video showing US troops firing on Iraqis from a helicopter came caches of documents from both the Iraq and Afghan wars, and a huge haul of classified state department cables.