This study evaluates group treatment for women suffering from chronic pelvic pain. The concept of group treatment was based on psychosomatic and physio-therapeutical principles and on cognitive and operant behavioral therapy. Each group was composed of up to six women suffering from chronic pelvic pain, and two physiotherapists. Each group treatment session lasted 2.5 h per week for a period of 10 weeks. The women completed questionnaires and pain drawings four times during the treatment period from the beginning of the period till 15 months later. During 13 group treatment periods 53 women accomplished the treatment. Before the treatment the women had experienced pain for an average period of 5 years and 9 months (ranging from 6 months to 22 years). The women's descriptions of the changes derived from group treatment were analyzed according to the Grounded Theory Method. A methodical triangulation of quantitative and qualitative data as well as analyzes of the drawings were applied. One year after the end of the treatment, 39% of the women were pain-free. The average level of pain measured according to the Visual Analog Scale was reduced from 2.8 to 0.9 (p < 0.01). The intake rate of analgesics was reduced from an average of 8.5 units to 0.9 units per week (p < 0.01). Furthermore a reduction in the use of the National Health Service and increases in gainful employment were registered. By means of the Grounded Theory Analysis a model of the development process was elaborated. The process begins with the development of self-knowledge, followed by the woman assuming self responsibility for her own life and performing self-activeness. During the process the woman increases her feeling of self-control and personal mastery of her emotions. The women's pain drawings improved, resulting in more detailed drawings, the color intensity abating, the extent of pains declining, and the outlines blurring. In conclusion this kind of group treatment brings the women relief from their pain thus reducing the use of the National Health Service by women suffering from chronic pelvic pain. The women also experience a positive psychological development. This method of treatment, in which a synergetic combination of physical and psychological treatment mutually enhance the effect of the treatment, will probably have a beneficial impact on the treatment of other patients suffering from acute or chronic physical or psychological traumas or from chronic pains.