This paper presents results of studies of ultrasonic and structural parameters of mortar. The objective of the study is to determine correlations between ultrasonic pulse velocity (UPV), porosity and permeability. The material investigated consists in seven mortar mixtures with water / cement ratio varying from 0.3 to 0.6. The paper is composed of three parts. The first one presents a description of the mortar samples that were subjected to ultrasonic, porosity and gas permeability tests and describes the details of those tests. Then, a simple model is proposed to relate ultrasonic pulse velocity with porosity and permeability. Finally, experimental results are shown and correlations between the measured parameters of the material are discussed. In the range of porosity values considered, the model correctly describes the dependence of UPV versus porosity and permeability. It could thus be used to predict the evolution of structural parameters of the material from non-destructive measurements.