This general report summarises the contributions on unsaturated soil mechanics submitted to the Discussion Session of TC106 – Unsaturated soils –at the 18th International Conference on Soil Mechanics and Geotechnical Engineering held in Paris in September 2013. The thirty-five papers collected under the framework of unsaturated soil mechanics cover a broad spectrum of problems and procedures at varying scales. Much attention is devoted to issues related to experimental techniques and procedures for hydro-mechanical characterisation of unsaturated soils, with special attention to retention behaviour. Swelling, shrinkage and eventually cracking are the processes which seem to capture most of the attention in view of the performance of engineering systems. A few contribution deal with constitutive and numerical approaches, while only a couple of papers introduce unsaturated soil mechanics into engineering practice. While innovative efforts are mainly addressed to experimental techniques in the laboratory, the most challenging issues in future perspective appear to be related to the assessment of unsaturated geotechnical systems in the field, including contaminated soils and mine tailings, besides to more traditional applications dealing with compacted soil structures and soil-atmosphere interaction.