The Committee for Scottish Affairs described the idea as a dead parrot in a report and asked the Scottish First Minister Alex Salmond to come up with a Plan B.
"The Scottish government tries to give the impression that a currency union is still a possibility. It is not. This parrot is dead," said Ian Davidson, chairman of the committee.
The report categorically stated: "If Scotland leaves the United Kingdom there will not be a currency union. Voters urgently need to be told what the Scottish government has as a Plan B."
The report released also dismissed Salmond's claim that UK Chancellor George Osborne and other UK MPs are bluffing by ruling out the proposal.
Also Read
"No future Chancellor could perform an about-turn on a currency union after a Yes vote in September's referendum without destroying both their political and economy credibility," the committee concluded.
Salmond's ruling Scottish National Party wants to share the pound with the UK in a currency union after independence, keeping the Bank of England safety net.
But this has been ruled out by all the main parties at Westminster, the report said.
"Despite the inherent risks involved, a new Scottish currency would give the Scottish Government the maximum economic leverage required to pursue a separate economic policy - the stated aim of separation," the report said.