No reason was given for the departure of Wheatcroft who has been in the job for just over a year having joined from The Times, where she was business editor, in March 2006.
Wheatcroft is well respected by News International and Rupert Murdoch and could be either a possible replacement for The Times editor Robert Thomson should he take up the job editing the Wall Street Journal. Alternatively Wheatcroft could not be a candidate to edit the latest newspaper to join the News Corporation stable.
Wheatcroft's departure follows a recent revamp of the paper that saw the introduction of a new layout and hand-drawn masthead to modernise its image.
Wheatcroft said: "I have enjoyed my time at The Sunday Telegraph, with such a great team, and I wish them every success."
Murdoch MacLennan, Telegraph Media Group chief executive, said: "It is a year since our move to Victoria began. We are now clearly seeing the success of that strategy with strong circulation figures for our papers and record numbers of unique users to our website. Today's editorial appointments will ensure we build on that success and maintain our position as the UK's leading quality multi-media business."
He added: "I'd like to thank Patience very much for her contribution to The Sunday Telegraph. We all wish her well for the future."
MacGregor was only appointed joint deputy editor of The Daily Telegraph in July 2006. He joined the paper from the Evening Standard where he had also been deputy editor for four and a half years.
He is replaced by Tony Gallagher who was appointed executive head of news at The Daily Telegraph in November 2006. He is another former Associated Newspapers journalist having formerly worked as assistant news editor at the Daily Mail.
In another change, Daily Telegraph editor Will Lewis will take on the additional duties of editor in chief across the two titles.
The Telegraph Group has witnessed a quick succession of editors since the Barclay brothers bought the two newspapers and subsequently moved the business to new headquarters in London's Victoria, which also resulted in a string of redundancies.
Lewis was named editor of the Daily Telegraph in October 2006. He took over from John Bryant, who had been acting editor of the paper since Martin Newland quit suddenly in November 2005.
Wheatcroft herself replaced Sarah Sands who lasted only eight months as the editor of the Sunday Telegraph before resigning. Sands replaced Dominic Lawson who edited the paper for ten years before he left in 2005.
In the July newspaper ABCs, The Sunday Telegraph, suffered a small dip in sales, with circulation down by 0.39% to 652,497 copies. Its six-month average figure, however, is down by 2.57% year on year to 656,234 copies.