The Supreme Court has dismissed an appeal by TD Joan Collins regarding the legality of the promissory notes.
She had argued that issuing the IOUs to bail out financial institutions was unconstitutional.
After having her case rejected in the High Court, Joan Collins appealed the decision to the Supreme Court.
Today they ruled the move by then Finance Minister Brian Lenihan to issue promissory notes was not unconstitutional.
The €31bn promissory notes were issued to allow Anglo Irish Bank and other institutions to access emergency funding from the Central Bank.
Deputy Collins argued they should not have been issued for a number of reasons, including the lack of a Dáil vote on the issue.
The six judges unanimously ruled that such power was permissible to be given to the Minister, given the economic circumstances and threat to financial institutions.
They added that a blank cheque is not in the power of the minister to issue without Dáil approval, and that it could not be seen as a template for broader ministerial powers because the circumstances were "exceptional".