The King spent time talking to new Foreign Secretary James Cleverly and Defence Secretary Ben Wallace as they were flanked by the Prime Minister.
He was introduced to members by the Prime Minister as they lined up inside the 1844 Room at Buckingham Palace.
Earlier members of the Cabinet were present for the formalities of the Accession Council at St James’s Palace, televised for the first time.
Camilla was also present at the audiences on Saturday afternoon and chatted to Cabinet members including Leader of the House of Commons Penny Mordaunt, who oversaw the Accession Council in her role as Lord President of the Council.
Following the Cabinet audiences, the King spent time meeting the leaders of opposition parties, including Labour leader Sir Keir Starmer.
Ms Truss, who only took office on Tuesday, had her own first audience alone with the King on Friday following his return to London from Balmoral.
Welcoming her to the Palace, Charles told her the passing of his mother was “the moment I have been dreading”.