Thomas Mair was told by an Old Bailey court judge in London that a provisional trial date has been fixed for November 14.
Mair was arrested at the scene of Cox's street killing last week, just days ahead of the crucial referendum to decide whether UK will stay part of the European Union or leave.
The 41-year-old Labour MP was shot and stabbed to death in Birstall, West Yorkshire, near her constituency office as she was holding a regular meeting with her constituents.
He has since been described as a far-right loner with mental health issues.
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He appeared today via videolink from Belmarsh Prison in south London and only spoke to confirm his name.
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Mair, who had denied the murder, did not take the witness stand to give evidence.
Justice Wilkie told the jury that they could draw inferences from the defendant'ssilence.
Mair was also found guilty of inflicting grievous bodily harm with intent to 78-year-oldBernard Kenny, who tried to stop the attack on Cox;possession of a firearm; and possession of a dagger.
She told jurors: "He was making motions towards us with the knife and Jo was lying in the road and she shouted out 'get away, get away you two. Let him hurt me. Don't let him hurt you'."
Describing the aftermath, colleague Fazila Aswat said: "Jo was in my arms. It was probably only two or three minutes before the ambulance arrived but it felt like a lifetime."
The attack was captured on grainy CCTV and witnessed by 16 members of the public who travelled to the Old Bailey court in London to give evidence.
Afterwards, Mair walked away as if he had "not a care in the world", the court heard.
Mair was a frequent visitor to Birstall and Batley libraries in the village of Birstall, where Cox was holding her constituency meeting on the day.
An investigation of his use of library computers exposed Mair's interest in far right, anti-Semitic and neo-Nazi politics in Britain and abroad.
When asked to confirm his name, the defendant, described by neighbours as a shy loner, said: "Death to traitors, freedom for Britain".