This volume contains the proceedings of the IUTAM Symposium on Ela- ohydrodynamics and Microelastohydrodynamics held in Cardiff from 1st to 3rd September 2004. The symposium focused on theoretical, experimental and computational issues in elastohydrodynamic lubrication (EHL) both in relation to smooth surfaces and in situations where the ?lm is of the same order or th- ner than the surface roughness (micro-EHL). The last IUTAM Symposium in this general area of contact of deformable bodies was in 1974. The emphasis in the Symposium was upon fundamental issues such as: solution methods; lubricant rheological models, thermal effects; both low and high elastic m- ulus situations; human and replacement joints; ?uid traction; dynamic effects, asperity lubrication and the failure of lubrication; surface fatigue and thermal distress under EHL conditions. Delegates were welcomed to Wales and the Cardiff School of Engine- ing by the head of the School, Professor Hywel Thomas. The opening l- ture was given jointly by Professor Duncan Dowson, FRS and Sir Gordon Higginson, the distinguished partnership which produced some of the most important numerical solutions to the fundamental EHL problem which led to the ?rst reliable ?lm thickness formula for isothermal, Newtonian conditions. Their presentation reviewed the early developments in the subject and included some fascinating details of the dif?culties overcome and the scienti?c pers- alities involved. A total of 33 presentations were given over a period of three days.