Margo MacDonald has introduced the bill to the Scottish Parliament
Most MSPs are opposed to plans to allow terminally ill people to seek help to die at a time of their choosing, a BBC Scotland survey has suggested.
Independent MSP Margo MacDonald, who has Parkinson's disease, has brought a bill to the Scottish Parliament.
A survey of two-thirds of MSPs showed 17 supported the bill, 53 said they were against and 20 were undecided.
Ms MacDonald said the results were better than expected and she was hopeful of winning further support.
MSPs are expected to vote on the bill for the first time in the autumn, with the legislation decided in a "free vote", rather than along party lines.
The survey, carried out by BBC Scotland's Politics Show, asked MSPs the question: "Are you, in principle, for or against the End-of-Life Assistance (Scotland) Bill that has been put forward by Margo Macdonald?"
MSPs were asked: "Are you, in principle, for or against the End-of-Life Assistance Bill?"
For - 17
Against - 53
Undecided - 20
Based on 90 replies out of 129 MSPs
The answers were given on an anonymous basis.
Ms MacDonald said most MSPs had not yet read the bill.
She added: "That looks as though there are 17 people out of the 90 who are absolutely convinced of the case already, which is further on than I thought it would be."
Asked if the legislation could win majority support, the Independent Lothian MSP, said: "I think we could perhaps - but whether or not we can win a majority of votes is another question.
"There is pressure being put on people but once the public, who are overwhelmingly in favour of this, start getting in touch with their MSPs, there will be MSPs, I think, taking some feeling of support from that, and they'd be much more likely to vote for the provisions of the bill."
While it is not illegal to attempt suicide in Scotland, helping someone take their own life could lead to prosecution.
The End-of-Life Assistance Bill would allow people whose lives become intolerable through a progressive degenerative condition, a trauma or terminal illness to seek a doctor's help in dying.
The bill has also proposed a series of safeguards to prevent abuse of the legislation, should it become law.
HOW THE BILL WORKS
A person must be terminally ill or "permanently physically incapacitated"
A request must be made to, and approved by, a doctor and psychiatrist
Both must be asked twice after 15-days cooling off period
Assistance must be supervised by the approving doctor
Close friends and relatives banned from administering drug
Only over-16s qualify
Applicants must be registered with Scottish GP for 18 months
Bill does not apply to those with dementia or other degenerative mental condition
Dr Gordon MacDonald, of the organisation Caring not Killing, said vulnerable people may feel under pressure to end their lives prematurely.
He said Ms MacDonald's bill was more about euthanasia than assisted suicide.
He added: "I actually think it's impossible to have a failsafe bill.
"Even in [the US state of] Oregon, which is held up often as being the best example that is available, there are stories of people who die in pain, there are stories of people who are depressed who get assistance to commit suicide."
Dr Libby Wilson, of Friends at the End, said it seemed "absolutely logical" to allow assisted suicide.
She said: "We've had battles in the past about allowing life to start and whether it should continue and, to my mind, we've won those battles, but it's quite logical people who have always been in charge of their lives should also be in charge of their deaths."