Donald Trump has said the foundation "must be shut down immediately"
Bill Clinton has said he will step down from the board of the Clinton Foundation if his wife Hillary is elected as US president.
The Clinton Foundation is a non-profit organisation that was founded by the former US president in 2001.
The foundation describes its aim as bringing together "businesses, governments, NGOs, and individuals" to help achieve global efforts such as improving health and wellness, reducing childhood obesity, and helping communities address the effects of climate change.
As Mrs Clinton's campaign for the presidency continues, the foundation has become a significant source of controversy for the candidate.
A number of e-mails are alleged to show links between the US State Department and the foundation during Mrs Clinton's time as secretary of state.
Only yesterday another set of e-mails released by the conservative Judicial Watch group claim to reveal the State Department gave "special access" to Clinton Foundation donors during Mrs Clinton's tenure.
Mrs Clinton's Republican rival Donald Trump has called for the foundation to be shut down.
In a statement yesterday, Mr Trump said: "The Clintons have spent decades as insiders lining their own pockets and taking care of donors instead of the American people. It is now clear that the Clinton Foundation is the most corrupt enterprise in political history.
"What they were doing during Crooked Hillary’s time as Secretary of State was wrong then, and it is wrong now. It must be shut down immediately," he added.
He also called for an independent special prosecutor to investigate any potential links between the foundation and the state department.
In a lengthy statement outlining what will become of the foundation if Hillary is elected, Bill Clinton has said he and his daughter Chelsea - who has had a "role in increasing scope and impact" in the foundation in recent years - have made it clear changes will be necessary if she is elected.
In the event of another Clinton reaching the White House, Mr Clinton explains that: "The Foundation will accept contributions only from US citizens, permanent residents, and US-based independent foundations, whose names we will continue to make public on a quarterly basis. And we will change the official name from the Bill, Hillary & Chelsea Clinton Foundation to the Clinton Foundation.
"While I will continue to support the work of the Foundation, I will step down from the Board and will no longer raise funds for it."
He also explains that any funding received by donor governments’ bilateral aid programmes will be 'transitioned' out and transferred to other organisations.
"While my role in that work will change, the work itself should continue because so many people are committed to it and so many more are relying on it," he adds.