This special issue of the Journal of Infrastructure Systems aims to provide an overview on advances of advanced Non Destructive Testing applied to civil engineering structures. Indeed we are at a stage where a substantial part of the infrastructure is entering a critical age. Dams, bridges, tunnels, pavements, nuclear power plants, etc. require sustainable maintenance to qualify for extension of their service life in good condition and safely with appropriate service level. NDT methods have their place aside more widespread visual inspections and destructive tests within this process even-though few standardised procedures exist. Due to their non intrusive nature NDT methods will play a prominent role in the future as more and more challenges specific to civil engineering problems, such as very large investigation zones and low cost requirements have recently started to be tackled by researchers and companies involved in this field (automation, imaging, optimised data acquisition procedures, signal processing., miniaturisation of the equipment etc.).