The week-long rebrand of the Department of Trade and Industry (DTI) to Productivity, Energy and Industry (DPEI) cost nearly £30,000.
The DTI's website - before it was changed back
The bill to the tax payer for the rebranding exercise has been criticised by the Tories who say the cash could have provided six hip replacements.
Tory frontbencher Lord Hanningfield said Tony Blair should pick up the bill out of his own pocket.
Minister Alan Johnson had played down the cost of changing the name back.
He said a "man with a screwdriver" would reattach the DTI name plate outside the ministry.
Lord Hanningfield said: "We now know that that man and his screwdriver cost us all £30,000.
"The cost of this fiasco could have paid for an additional police officer or six hip replacement operations.
"This whole episode revealed yet again that Tony Blair is more interested in renaming and rebranding Whitehall than renewing and reforming Britain. If anything Tony Blair should pay for this out of his own pocket."
Loss of 'trade'
The Department of Trade and Industry is to revert to its name after briefly being re-branded as the Department for Productivity, Energy and Industry.
It is understood the Mr Johnson, then just appointed trade secretary in the post-election reshuffle, persuaded the premier to change the name back following criticism from business leaders and unions.
He said there was concern about the loss of the word "trade" in the title.
And DPEI had prompted "various descriptions...penis and dippy", he said.
The cost of the name changes were revealed in a Commons written answer.