The former church of “San Gregorio” in Venice is a deconsecrated church of the IX century, located near the Basilica of “Santa Maria della Salute”. The surveys on the building were carried out to determine the mechanical properties and construction techniques of the structural elements. In particular tests with (single and double) flat jacks, videoendoscopic investigations, sonic tests, dynamic tests for the determination of the strain of the steel rods and characterization of the timber elements through visual and resistographic examinations were carried out.