Gaydamak, 56, was born in Moscow in 1952, and immigrated to Israel at the age of 20. He made his fortune, estimated at over $8 billion, by pursuing a lucrative import-export business.
The businessman gained popularity in Israel for his charity work. He also owns the soccer club Beitar Jerusalem. His son, Alexander, owns the English soccer club, Portsmouth.
In February 2007 he announced the establishment of his own Israeli social movement, Social Justice, which became a political party in July 2007.
The frontrunners in the elections are an ultra-Orthodox rabbi, Meir Porush, who has support among secular and national-religious voters, and Nir Barkat, who made his fortune by investing in high technology.
The fourth mayoral candidate is Dan Biron, an ex-director of public television turned bar owner and head of the Green Leaf party, which calls for the legalization of marijuana.
Jerusalem will elect a new mayor as part of municipal polls held throughout Israel on Tuesday. The current campaign is viewed as a preparation for the February parliamentary elections.