Two weeks after the MSP died at her home, the campaign backing her Bill has revealed a surge in support since its launch at the start of the year.
My Life, My Death, My Choice, which brings together groups in favour of changing the law, said the number of signatures on their petition now stands at 1615.
Ms MacDonald's Bill, which is progressing through the Scottish Parliament, gives patients the option of taking their own lives with the support of trained facilitators as long as they comply with a number of safeguards.
Bob Scott, spokesman for My Life, My Death, My Choice, said: "Public support for a change in the law is at an all-time high and this issue is very much something that needs to be looked at closely."
He continued: "We launched the campaign on the back of the poll results which showed there was a large amount of support for the Assisted Suicide Bill in Scotland. However, we have been heartened by the strength of feeling and number of people who feel that this should now become law.
"At every event we've attended we've been moved by individuals who recounted personal experiences of a loved one suffering an undignified and intolerable death. If this Bill were to be passed people could be provided with appropriate information to mke their own individual choices and, in certain limited circumstances, given assistance to end their life."
My Life, My Death, My Choice has held a number of events at party political conferences this year - supported by a surprise legacy which was received by the Scottish organisation Friends at the End.
There was standing room only at some of the meetings.
Andrew Morrison, an approved candidate for the Scottish Conservatives, said he was opposed to Ms MacDonald's first attempt to legalise assisted dying in Scotland.
This Bill fell after failing to receive enough support in Holyrood in 2010.
However, Mr Morrison has since written about a change of heart influenced both by the event at the Scottish Conservative Conference and his own grandmother's deterioration after being diagnosed with bowel cancer.
He described his grandmother suffering a long period of sleepless nights and lifeless days, interspersed with shots of morphine.
At one point, he said, she refused to sit or lie down for fear of falling asleep and "slipping into death". This wasn't, he said, because she didn't want to die, but because she wanted to die at the right moment for her.
Mr Morrison said: "It is not an easy thing to think about and you need to make a conscious effort to do it and try to put yourself in the shoes of a family member who is facing circumstances like these and wonder what they would want."
A spokesman for Care Not Killing, the umbrella group opposing the bill, said: "It is difficult to see how fewer than three hundredths of one per cent of Scots signing a petition constitutes anything which might be considered even close to significant levels of support.
"Margo's last bill was defeated by an overwhelming majority of 85-16 in 2010 and the safeguards in this latest bill are equally paper thin."