A better definition of the properties needed by mortars used in the conservation of ancient masonry is necessary in order to prepare the way for the drafting of specifications and standard testing procedures. Standard samples of mortars composed of lime, lime/cement, lime/pozzolana, and lime/brick powder were submitted to the following tests: setting time, compressive strength and modulus, flexural strength, pore size distribution, extraction of alkaline materials. Test results show that it is possible to prepare reliable mortars which are easy to apply and have properties not too dissimilar from those of traditional materials. See also AATA 19-1792.