This special volume is composed of extended versions of selected papers presented at the 33rd annual conference of the EURO Working Group on Operational Research Applied to Health Services (ORAHS'2007, July 15–20, 2007, Saint Etienne, France). Other quality papers are also included to have a more comprehensive view of applications of operations research to health services. The EURO Working Group on Operational Research Applied to Health Services was formed in 1975 as part of a program for developing special interest groups within the European branch, EURO, of the International Federation of Operational Research Societies, IFORS. The group meets every summer, for one week in a different host country, usually in Europe. Meetings are open to anyone with a quantitative background and an interest in the subject area. The objectives of the group are communication of ideas, knowledge, and experience concerning the application of Operational Research (OR) approaches and methods to problems in the area of health services, as well as mutual assistance among members, co-operation on joint projects, and inspiration with regard to approaches and attitudes in this field.