Chaudhry, who became Fiji's first ethnic Indian prime minister in 1999 but was ousted in a coup a year later, was found guilty last month on three counts of giving false information to tax authorities about bank accounts in Australia.
The High Court in Suva refused a request from Chaudhry's lawyers for the charges to be dismissed with no conviction recorded and fined the 72-year-old politician Fij dollar 2 million (USD 1 million).
The conviction means the Fiji Labour Party leader cannot run in Fiji's general election in September, the first to be held since acting prime minister Frank Bainimarama seized power in a bloodless coup in 2006.
Under Fiji's constitution, anyone who has been convicted of a criminal offence in the past eight years cannot stand in the election. Another former prime minister, Laisenia Qarase, is also out of the running after he was found guilty of corruption charges in 2012.
After that case, Amnesty International accused the Bainimarama regime of using politically motivated charges to silence its critics.