On graduation in 1975 he became the consultant gynaecologist and obstetrician at St Bartholomew's Hospital and Homerton Hospital, holding both positions until 2000. He was a consultant at: Whittington Hospital (2000–2008); King Edward VII Hospital for Officers; director of the Fertility Unit at the Portland Hospital (1987–94): med director of the Homerton Hospital (1994–1997). His last position before retirement from the National Health Service (NHS) in 2008 was as consultant obstetrician and gynaecologist at the Whittington Hospital, London.
Setchell was a council member of the Royal College of Obstetricians and Gynaecologists from 1994 to 2000. A council Member of King Edward VII Hospital, and a trustee of the charity Wellbeing of Women, he was made Commander of the Royal Victorian Order in 2005.
Surgeon-Gynaecologist to the Royal Household
Having replaced Sir George Pinker in 1990, Setchell serves as Surgeon-Gynaecologist to Queen Elizabeth II. Setchell delivered Lady Louise Windsor at Frimley Park Hospital, the first royal child to be delivered at an NHS hospital, and Viscount Severn. He also cared for their mother, the Countess of Wessex, after her ectopic pregnancy in 2001 and assisted with the Duchess of Cornwall's hysterectomy. In December 2012, he attended Catherine, Duchess of Cambridge, in her pregnancy. He delivered her son, Prince George of Cambridge, in July 2013 at the Lindo Wing of St. Mary's Hospital in Paddington.
During his time as Surgeon-Gynaecologist to the Royal Household, Setchell attended Cherie Booth to deliver her and Tony Blair's fourth child, Leo. Leo was the first legitimate child born to a serving Prime Minister in over 150 years – since Francis Russell was born to Lord John Russell on 11 July 1849.
- Progress in Obstetrics and Gynaecology (1987)
- Scientific Foundations of Obstetrics and Gynaecology (ed, 1991)
- Reconstructive Urology (1993)
- Ten Teachers Gynaecology (1995)
- Ten Teachers Obstetrics (1995)
- MCQ's in Obstetrics and Gynaecology (1996)
- Shaw's Textbook of Operative Gynaecology (2001)
- Self-Assessment in Gynaecology and Obstetrics (2001)
- General Surgical Operations (2006)
- "Marcus Setchell, Esq, CVO Authorised Biography". Debrett's. Retrieved 30 July 2013.
- "Birthday Honours List – United Kingdom". The London Gazette. 12 June 2004. Retrieved 30 July 2013. "C.V.O. – Marcus Edward Setchell, Surgeon-Gynaecologist, Royal Household."
- "2003: Royal baby born prematurely". BBC News. 8 November 2003.
- Eden, Richard (30 January 2010). "The Queen's doctor is sued in High Court for £300,000". The Telegraph.
- Davies, Caroline (22 July 2013). "Royal baby: Queen's gynaecologist leads top medical team". The Guardian. Retrieved 30 July 2013. "The royal baby is to be delivered by a top medical team headed by the Queen's gynaecologist Marcus Setchell, who delayed his retirement after being asked by the Duke and Duchess of Cambridge to oversee the birth."
- Davies, Caroline (24 July 2013). "Prince of Cambridge's parents present him to the world at first photocall". The Guardian. Retrieved 29 July 2013. "As is traditional, the birth announcement also appeared in the Court Circular, the published diary of royal engagements which was started by George III in 1803. It read: "KENSINGTON PALACE 22nd July, 2013. The Duchess of Cambridge was safely delivered of a son at 4.24 p.m. today. Her Royal Highness and her child are both well. Signed: Marcus Setchell, Guy Thorpe-Beeston, Sunnit Godambe, John Cunningham." The signatories are the medical team who attended the duchess during the birth."
- Rayner, Gordon (22 July 2013). "Duchess of Cambridge gives birth to baby boy". The Telegraph. Retrieved 30 July 2013. "The Queen's gynaecologist, Alan Farthing, was not present."
- "Facts: Life and times of Tony Blair". CNN. 10 May 2007. Retrieved 30 July 2013.
- Assinder, Nick (20 May 2000). "Welcome distraction for Tony Blair". BBC News. Retrieved 13 July 2010.
- Bailey, Charlotte (26 Sep 2008). "Jill Dando's fiancé to be the Queen's doctor". The Telegraph. Retrieved 30 July 2013.
- Eden, Richard (28 July 2013). "Prince George's doctor Maurice Setchell to be given retirement gift". The Telegraph. Retrieved 30 July 2013. "Mandrake hears that Setchell, who will retire as the Queen's surgeon/gynaecologist at the end of this year, is in line to receive a knighthood or be admitted into the Royal Victorian Order in the next honours list."