New candidates for the reshuffled European Commission have won support from MEPs after grillings at the European Parliament.
Frattini replaces Buttiglione in the new commission line-up
Hungary's Laszlo Kovacs, Italy's Franco Frattini and Latvia's Andris Piebalgs were interviewed on Monday and Tuesday.
Commission chief Jose Manuel Barroso had been forced to change his proposed team after it became clear that MEPs would reject his original line-up.
A vote on the reshuffled commission is due to take place on Thursday.
Mr Frattini was questioned by MEPs for three hours on Monday.
He refused to condemn the views of his predecessor Rocco Buttiglione, which had in part led to the reshuffle.
Mr Buttiglione, when nominated as justice commissioner, had upset MEPs with his conservative views on women and homosexuals.
The threat that the commission would be rejected meant Mr Barroso reshuffled his team, with Mr Frattini in place of Mr Buttiglione.
Mr Frattini told the panel that he would promote tolerance and uphold minority rights.
The BBC's Chris Morris said it was a confident performance in the face of some fairly searching questions.
At one stage he was forced to deny that he was a Freemason and at others he had to insist that he would remain entirely independent of the Italian government led by Silvio Berlusconi.
But Mr Frattini said he would represent Europe as a whole, not a political party in Italy.
MEPs are reported to have said he gave "a convincing impression of his personal and professional capacity" for the job.
Questions had also been raised over the original choice of Mr Kovacs for the energy portfolio after his disappointing performance in his first nomination hearing.
But he is said to have redeemed himself on Tuesday as he sat for the taxation and customs job in the reshuffled commission.
He said he was in favour of fiscal competition and was against a French proposal to cut aid to new EU member states who attract investors with lower corporate tax rates.
He said companies did not move from one country to another for that reason alone.
"Fiscal competition is not damaging as such," he said.
He also defended having been a member of the Communist Party before 1989, which has drawn criticism from some parts of the EU. He denied claims that he had been part of the workers' militia or relations with the secret services.
"In my background, there is nothing to hide and nothing to be ashamed of," he said.
Some analysts say Mr Kovacs came across as better prepared than for the energy portfolio hearing before the reshuffle.
Mr Piebalgs is said to have had no problem convincing the Industry, Research
and Energy Committee of his fitness to be energy commissioner.
The head of the European People's Party, Hans Gert Poettering, said: "I'm going to recommend to my group that we give very solid support to the commission on Thursday, and I have no doubt that the great majority of my group will follow that recommendation."