Save the 8th campaigners are expecting tens of thousands of people to join their march this afternoon.
The organisers of today's 'All Ireland Rally for Life' in Dublin say it's more important than ever for Irish people to take to the streets to let their feelings be known.
The rally is getting underway at 2pm at Parnell Square.
Organisers say the rally will feature speakers who will share personal stories of crisis pregnancies, abortion and regret.
Spokesperson Niamh Ui Bhriain says the government has got it wrong about the referendum.
"I think we can see in the polls that support for repeal and support for this particular proposal is already dipping," she said.
"I think the government has seriously misunderstood where people stand on this issue and we're going to see that the referendum will be lost on May 25th," she said.