Sandstones occurring in many localities in the Carpathians have been quarried for ages and applied to constructing, particularly in the Małopolska region, as building and decorative rocks. Utilization of specific types of sandstones is controlled essentially by such their properties as colour, grain-size distribution, a possibility of quarrying without serious technical problems quarrying and obtaining large blocks. Diversified lithological development of sandstones results in the differentiation of their physical and mechanical parameters and, consequently, decides about variable resistance to the action of damaging factors and, thus, controls their application in the building sector. Crystallization of salts is one of these factors as it may sometimes lead to a total destruction of the stone. This process is particularly intensified in the strongly contaminated environment of urban agglomerations. The authors have determined the open porosity according to the PN-EN 1936: 2001 standard and the resistance to salt crystallization according to the PN-EN 12370: 2001 standard of the Carpathian sandstone types most often applied to building purposes, namely the Lgota, Godula, Istebna, Ciężkowice, Magura and Krosno sandstones. Having the tests completed, microstructural changes of the rocks were investigated in the scanning electron microscope (SEM). The observations were made on two sample series: one included the rocks after 15 cycles of impregnating with the 14% water solution of Na2SO4 and drying, the other represented the rocks additionally rinsed with water after the impregnation. It has been established that the sandstones are characterized by variable sizes of pores and the open porosity in the range 2.9-12.8%, resulting from the diversified content and type of rock cement. In the process of salt crystallization, the first to be filled are larger pores, then the smaller ones. The main cause of rock destruction is the stress developed in the rocks due to crystallization of hydrated and ahhydrous sodium sulphates (mirabilite/thenardite). The SEM observations have proved that it is not the value of their open porosity which decides on the resistance of the sandstones to salt crystallization, but it is the type of the rock cement and the way in which the cement fills intergranular spaces of the sandstones. This finding refers both to the rocks of considerable open porosity and to those with their porosity values below 5%; in the case of the latter it is particularly important as the tests for salt crystallization are not stipulated by the standards. The most salt-resistant are Magura and Ciężkowice sandstones, whose cement is dominated by carbonate minerals and silica. A substantial resistance is also revealed by Lgota sandstones, in which the siliceous cement, although scarce, rather strongly binds the grain framework. The Istebna sandstone samples disintegrated in the tests, as they have practically no resistance because of their low content of cement, in which clay minerals prevail. Disintegration also affected the Godula sandstone samples, despite their showing a slightly higher content of siliceous-clay cement.