Health-related quality of life (HRQOL) , abbreviated as QOL, can be evaluated by various questionnaires, which are classified as generic and disease-targeted ones. Generic questionnaires are further subdivided into profile-type and preference-based ones. SF-36 and EQ-5D are the best known examples for the former and the latter, respectively. In SF-36 and its shortened one SF-8, the subjects' QOL is expressed by several profiles or subscales. Their advantages include well-conducted validation and availability of national norms. In EQ-5D, a single value representing the subjects' QOL status (utility) is obtained through 5 questions. These generic questionnaires are applicable to patients with various diseases or even to healthy citizens. In contrast, disease-targeted questionnaires lack such features, but can include items that are specifically related to the disease but devoid of general applicability. Thus, generic and disease-targeted questionnaires have their own pros and cons. Selection of the questionnaires depends on the object of the study.