The shear properties evaluation on existing unreinforced masonry structure is usually performed through destructive tests. However, these tests have the characteristics of being very expensive and require significant damage not only on the samples but also on the portion of wall surrounding them. The present work illustrates the design of a new testing procedure for the characterization of the shear properties in masonry panels for application in routine testing. In the aim of preserving the integrity of the area under testing and to reduce the cost of the new testing procedure, it has been decided to use flat jacks. The numerical analyses used to design the test are presented as well as the results of a first application of the procedure.