The recent development of a new Italian seismic code, conceived as a transition towards the final adoption of Eurocodes, has been an occasion to reconsider thoroughly the current criteria for seismic design of masonry buildings, their experimental and theoretical basis, their consequences on practice. Drawing from this experience, a critical discussion of design criteria is presented, with specific attention to the definition of behaviour factors to be used in elastic analysis and more generally on methods and models for the seismic performance verification of masonry buildings. Necessary and possible developments of design/assessment procedures and code provisions are presented, and research needs are outlined.