A method for testing the hermetic seal of a packaged device, which includes: a package that delimits a device chamber; and a transducer device, which is arranged within the device chamber and generates an electrical signal indicating at least one physical quantity external to the package. The testing method includes the steps of: imposing a reference pressure in the device chamber; arranging the packaged device in a testing chamber in which a testing pressure is present, different from the reference pressure; and subsequently detecting possible pressure variations within the device chamber.