The Quebec Court of Appeal dismissed a Quebec government bid to force Ottawa to keep data related to the federal long-gun registry.
Quebec also wanted police forces to continue to have access to the data.
The judgment comes four weeks after the same court overruled a lower court and said the federal government's destruction of the data was constitutional.
In the June 27 judgment, the appeals court said the province had no right to the registry data. It also ordered the provincial government to pay the court costs for the case.
The provincial government had already announced plans to appeal that decision to the Supreme Court of Canada.
Quebec Justice Minister Bertrand St-Arnaud reacted quickly to Tuesday's ruling by saying the province would launch an immediate appeal with the Supreme Court to prevent any destruction of documents.
Ottawa has already deleted registry data pertaining to other provinces.
Tuesday's judgment is just the latest round in a legal battle over an emotional topic in Quebec, where the fight for gun control intensified in the wake of the 1989 Polytechnique massacre.
The bill to scrap the federal registry received royal assent in April 2012, fulfilling a longstanding pledge by the Harper government.
Opponents of the registry called it wasteful and irrelevant in stopping crime. Its supporters, however, including some police organizations, described the registry as a valuable tool in law-enforcement's arsenal.
Quebec has argued it needs the data to support its own gun registry _ making it the only province to announce its intention to do so.
The province has argued it would cost too much to start the registry anew.
Lawyers for the federal government have argued that if Quebec wants a registry of its own, it should start from scratch. The Conservative government has vowed to fight to ensure all the data is destroyed.
Both sides have called the case a legal first in Canada.
On Tuesday, appeals court justice Pierre Dalphond dismissed Quebec's argument that starting from scratch would be an onerous financial burden.
He also cast doubts on whether the destruction of data would deprive police officers of a worthwhile tool and expose society to more violence.
''Police forces elsewhere in the country have been functioning without (such) a registry since October 2012 and there's nothing to suggest that that has led to irreparable or even serious harm,'' he wrote.
''Statistics and studies from the last 30 years don't appear to establish a correlation between the registering of long guns and the drop in homicide rates. As well, nothing suggests the number of crimes committed with long guns has increased in other provinces since October 2012.''