The aim of the study is to assess the effect of weathering on acoustic properties of mortars. X-ray micro-tomography was used to monitor the physical changes of mortar samples undergoing weathering cycles. Infunction of the number of cycles, the weathering zones were quantified as well as the appearance of fractures in three dimensions. This information was used as input to model acoustic parameters and validated with the macroscopic parameters and sound absorption spectrum which was quantified before and after weathering.