Ahmad Mekki of the judges club said the panel reprimanded Hisham Bastawisi and cleared his colleague, Mahmoud Mekki.
The verdict came as Egyptian police clamped down on demonstrators supporting the judges in Cairo by sealing off the city centre and arresting more than 200 members of the Muslim Brotherhood.
Protesters, who had come out to show support for the two men facing disciplinary proceedings, were kicked and clubbed by plain-clothes security men.
The judges' case has provoked clashes between police and demonstrators, and on Thursday thousands of officers sealed off the centre of Cairo.
Hundreds of arrests were made, the majority being members of the Muslim Brotherhood opposition group, which is officially illegal.
Plainclothes police officers arrest
protesters in Cairo
Abdel Moneim Abul Futtuh, one of the Islamist movement's leaders, said: "A total of 210 of our supporters have been rounded since this morning."
He told AFP that among those arrested were the movement's spokesman Issam al-Aryan and the former leader of the Muslim Brothers' parliamentary group Mohammed Mursi.
In the same High Court building on Thursday, the Court of Cassation rejected an appeal from imprisoned opposition leader Ayman Nour, and confirmed his five year jail sentence handed out last year on forgery charges which he and his supporters say are fabricated.
The US government condemned Nour's continued detention, describing it as "a miscarriage of justice".
"Both Mr Nour's ongoing detention and the Egyptian government's handling of dissent raise serious concerns about the path of political reform and democracy in Egypt," said spokesman Sean McCormack.
In a crowded market area north of the High Court complex, photographer Tara Todras-Whitehill said thugs backed by riot police chased a group of about 800 people down the street and attacked any stragglers.
Issam al-Aryan was among those
arrested, the Brotherhood said
"They took those closest to the end while the other demonstrators dispersed. I saw at least 20 people being beaten with fists and kicks and short clubs," she said.
In one of the city's main shopping avenues, security men hemmed in about 200 protesters affiliated to the Kefaya (Enough) Movement, which campaigned last year to stop Hosni Mubarak, the president, getting a new term in office.
One of the two judges, Mekki, went to the High Court complex with a large delegation of judges but set conditions for attending the disciplinary hearing.
As the judges passed, supporters threw roses at them from the steps of the Journalists Syndicate, a popular protest spot.
Mekki said the judges wanted security forces to leave the area, release everyone detained for protesting, and the judicial authorities to remove Fathi Khalifa, the president of the Court of Cassation, from the disciplinary committee.
His colleague, Bastawisi, did not attend because he had a heart attack on Wednesday and is still in hospital.