This special issue contains a selection of invited, full-length, peer-reviewed manuscripts from participants of the international workshop “Water in Pavements WIP’05”, held in Madrid, Spain on 27th October 2005. The presented papers give a complete picture of the recent developments in the area of mechanical and environmental aspects of the water in pavements. In particular, they address performance-related properties, modelling and the monitoring of water flow and moisture within pavements and subgrades. The guest editors of this issue are grateful to the authors for their excellent effort and for their patience during the peer review process. A special thanks also goes to the reviewers for their time and effort in improving each of these papers. This special issue is a part of the dissemination activities of the COST 351 European Action on Water Movements in Road pavements and Embankments WATMOVE (chaired by Andrew Dawson, University of Nottingham). It constitutes a suitable overview of the most innovative research on water in pavements, and it is to be associated with the soon-to-be published book by the WATMOVE team.