Descôteaux v Mierzwinski, [1982] 1 SCR 860 is a leading Supreme Court of Canada decision on solicitor-client privilege.

The police were investigating the legal aid bureau in Montreal in relation to a charge on Marcellein Ledoux for falsely stating his financial status in order to qualify for the services.

Justice Lamer, writing for a unanimous court, held that the documents were not wrongly seized.

The trial court erred when dismissing the motion for certiorari to quash the warrant, but not because the documents were privileged.

However, the legal aid application falls within one of the exceptions to solicitor-client privilege, known as the crime-fraud exception: any communication made for the purpose of obtaining legal advice to facilitate the commission of a crime, or any communication which itself is the material element of a crime, does not benefit from the principle of privilege.