Asked by reporters as he was leaving how his meeting with the Queen had gone, Mr McGuinness said it had been "good" and had "went well".
Before getting in his waiting car, Northern Ireland’s deputy first minister the said: "I'm still a republican."
It is understood that during their initial private meeting, Mr McGuinness welcomed the Queen in Irish.
Mr McGuinness is said to have commented briefly on the Queen's visit to Dublin last year, and in particular her comments regarding all the victims of the conflict.
A Sinn Fein spokesman said: "He emphasised the need to acknowledge the pain of all victims of the conflict and their families."
Sinn Fein said Mr McGuinness told the Queen that their meeting was a "powerful signal that peace-building requires leadership".
