The aim of this study is to evaluate comparatively the life quality of patients with knee osteoarthritis (KO), shoulder impingement syndrome(SIS), fibromialgia(FM), or osteoporosis(OP) using SF 36 and establish the impact of these diseases on quality of life (QoL). A total of 193 patients with one of the above-mentioned different diagnoses completed SF 36 scale. The diseases were compared to each other with SF 36 subgroups scores. There were significant differences among patients with KO and SIS, SIS and FM with respect to all SF 36 subgroups scores. According to these assessments, QoL of KO and FM patients was worst than that of SIS. The QoL scores of KO patients were worse than those of FM patients considering the physical function, while QoL scores of FM patients were lower than those of KO patients with respect to their general well-being. Scores of physical function and pain in KO patients were lower than those of OP patients. In domains of social functioning, emotional role, energy, pain, and general health condition QoL of FM patients was worse than that of OP patients. Quality of life of SIS patients was less affected than the patients of the other disease groups. In spite of their young age, FM patients appear to be the group with the worst quality of life scores.