Hanson and her former colleague, David Ettridge, were each given three year terms by a Brisbane court, on Wednesday.
The 49-year-old firebrand and Ettridge, 58, pleaded not guilty to fraudulently registering the One Nation party they founded in 1997.
Hanson also denied dishonestly obtaining almost 33,000 US dollars in electoral reimbursements after the 1998 Queensland state election.
But the 12-member District Court jury found the pair guilty on all charges, after more than nine hours of deliberation.
Hanson told the hearing during sentencing submissions: "I'm still very innocent of the charges and I believe the prosecution has not proven the case against me or David Ettridge."
"Rubbish, I'm not guilty... it's a joke."
-- Pauline Hanson, One Nation party leader
As the verdicts were announced she said angrily: "Rubbish, I'm not guilty... it's a joke."
The 23-day trial heard allegations the pair lied to get the party registered by pretending that more than 500 people used in the electoral application, belonged to the party.
The prosecution argued that the people belonged to Hanson's support movement and not to the party.
Prosecutor Brendan Campbell told the court the pair had undermined the political process.
The former fish-and-chip shop owner rose to national prominence in 1996 after the centre-right Liberal Party, headed by Prime Minister John Howard, dropped her as a candidate for a seat in federal parliament.
But she stood as an independent, won a seat and shot to international notoriety over her views on Asian immigration and Aborigines.
Hanson railed against welfare payments to Aborigines and said Australia was being "swamped" by Asians.
The peak of her popularity came in the 1998 Queensland state election when One Nation won 11 seats and captured almost 25 percent of the vote.
But soon after, internal feuding split the party, consigning it to the electoral fringes.
But Hanson claimed Howard stole her policies when he adopted a hard-line stand against illegal immigration, which polls have shown is supported overwhelmingly by Australians.
Howard: Under pressure to sack
Meanwhile, John Howard was under pressure on Wednesday to sack a minister accused of misleading parliament.
Regional Services Minister, Wilson Tuckey, has admitted trying to use his influence to get his son off a traffic fine.
Tuckey intervened unsuccessfully to overturn 126 US dollar fine imposed on his son for driving a truck without a logbook.
But he is also accused of misleading parliament by claiming he only sought to make representations to the police on behalf of a constituent.
It has emerged his son, Michael, is not a constituent as he lived in a different electorate and Tuckey wrote three times on ministerial letterhead seeking to have the fine dropped.
Tuckey apologised to parliament on Wednesday for using a ministerial letterhead and admitted he erred in referring to his son as a constituent.
Nevertheless, the opposition is still demanding his sacking.
The row comes at an inconvenient time for Howard, himself facing accusations of misleading parliament over a meeting with a businessman whose product later won generous government subsidies.
At least five ministers were sacked or forced to resign for breaching ministerial behaviour rules during Howard's first term, after he took office in 1996.