The party's deputy leader was the only candidate to succeed Mr Adams when nominations closed this morning, Sky News reported.
A Claire Byrne/Amarách poll for the TheJournal.ie asked people: "Would you be more likely to vote for Sinn Fein under the leadership of Mary Lou McDonald?"
Sinn Fein's high council met in Belfast today to formally ratify the nominee for president and a special party conference to elect the new leader will be held next month.
"I know I have big shoes to fill taking on the role from Gerry Adams, and I know that is impossible", McDonald said.
In Belfast, Mr Adams, the Sinn Fein party president for three decades, said: 'We need to have a party that's fit for objective, we need to have a plan.
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Meanwhile, Bulgaria's Grigor Dimitrov defeated Dennis Novak 6-3, 6-2, 6-1 in the match which lasted over one hour 38 minutes. Opens a year ago but had his preparation for Australia delayed because of an injured right knee.
Mr Adams also used the Belfast gathering to indicate Sinn Féin wants to see an end to the stalemate at Stormont.
She became Sinn Fein's first MEP in the Republic of Ireland in 2004 and Blevins said she had "lots of political experience and is well known for voicing her views, rather strongly on occasion".
Mr Adams added: "Separate development and negative divisions are not good for our community". We also have to challenge unionism.
He also said: "Whether the upcoming talks succeed or not in the short term, there is no merit in Sinn Féin disengaging from the conversations and dialogue with unionists and others that are necessary".
"Little was I to know at that time that I would come to know and work so closely with Gerry and the entire leadership and to have him as such a close friend", she said.