Natural stone has always been one of the main materials used in architecture for its singular beauty and durability. However, ornamental and structural stone elements might show decay essentially induced by climate factors such as atmospheric pollution, freezing–thaw action, thermal shock or acid rains. The deterioration of natural stone doesn’t concern only a worsening of its aesthetical properties, but mostly a decreasing in mechanical strength. To detect and to analyse the dominant destructive factors for stone durability is important to forecast the trend of the deterioration in the long term. For this reason, the comparison of the natural weathering with the results of artificially ageing tests on the same kind of stone is useful. This research compare the decay artificially induced in laboratory (according with the test method foreseen by European standard to evaluate the durability) with the one caused by natural ageing (with the action of the different climatic agents). In laboratory, six different kind of stone and in particular marble, sandstone, limestone, gneiss, granite and tephra, have been tested by means of two different artificial ageing tests: determination of resistance to ageing by means of thermal shock and freeze and thaw cycles. In order to assess the variation of mechanical resistance, flexural strength tests under concentrate load and ultrasonic test have been performed before and after the artificially ageing cycles. The tested stone gave different variations in mechanical strength for the two different artificial ageing test. This different behaviour have been explained by means the analysis of petrographic characteristics of the stone tested. Finally, a comparison of three case study of natural weathering of stones in historical building in different climatic zones of Europe have been made. For the evaluation of in situ decay, the study has been focused on marble, granite and gneiss, recognising their main weathering forms and comparing them with those obtained with the artificially ageing tests.