The 4th International Conference on Long-Term Behaviour and Environmentally Friendly Rehabilitation Technologies of Dams (LTBD 2017) will be held from 18th - 20th October 2017 in the International Conference Centre in Tehran, Iran. On behalf of the Iranian Committee on Large Dams, IRCOLD, and the International Committee of LTBD, it is our pleasure to invite you to participate in this conference which will provide an excellent opportunity for high level scientists, engineers, operators and young PhD students to present and exchange their experiences and the latest developments related to the design, performance rehabilitation and environmental aspects of earth, rockfill and concrete dams.