Now the two men appear to have patched up their differences, with Mahathir’s aides saying on Wednesday that the two had agreed to meet.
There was no indication on what grounds Soros had sought the meeting, but online newspaper Malaysiakini has quoted the financier as saying Mahathir and he now held some ideas in common.
Malaysiakini quoted Soros as saying in an interview earlier this year: "I think Mahathir has made a great contribution to Malaysia's material development, but like all great men, he has made some great mistakes.
"There are many areas where we think alike, and I'll be happy to engage in a dialogue with him."
Soros is ranked number 27 in Forbes' list of 400 richest Americans in 2006, with a net worth of $8.5bn to his name through hedge funds.
Mahathir, who stood down as Malaysian prime minister in 2003, suffered a mild heart attack last month, but has since returned to work.