Conflict between doctors, patients and relatives can usually be avoided through 'early, sensitive discussion and planning about how best to manage the patient's care', the GMC says.
The advice is laid out in Treatment and care towards the end of life: good practice in decision making, published last week.
The report urges doctors to make a record of discussions with patients about future care, as well as the decisions made.
Advance care plans will need to be reviewed and updated as the patient's situation or views change, the guidance says.
A GMC spokeswoman said: 'Doctors now need to identify patients for whom advanced care planning might be appropriate. They need to start thinking about who the patients are, and how to have a sensitive conversation with them about their future care.' Niall Dickson, chief executive of the GMC, said: 'Advance care planning is about talking to patients about what it is they want to do, so you can understand that and make the necessary arrangements to make it more likely their wishes will be carried out.'
Serious or persistent failure to follow the guidance could put doctors' registration at risk, the GMC warned.
Dr Tony Calland, chairman of the BMA's medical ethics committee, said: 'The GMC's guidance is clear on the need to work with the patient or, where appropriate, their relatives or advocate to ensure they are treated fairly, with dignity and without prejudice.'
Former RCGP chairman Dr Mayur Lakhani, now chairman of the National Council for Palliative Care and the Dying Matters Coalition, said: 'The emphasis that the GMC's new guidance puts on the need for open and honest conversations between doctors, people app-roaching the end of life, and those close to them is welcome.'