Purpose. To study the impact on health status as measured by SF-36 in groups of subjects having chronic musculoskeletal pain with different degree of generalization: No chronic pain ( NCP), chronic regional pain ( CRP), chronic widespread pain ( CWP), CWP with a stricter `Manchester' definition (CWP-M), and clinically defined. bromyalgia ( FM). The study also examines the association between psychosocial and lifestyle background variables, and these pain-groups. Method. A cross-sectional study with a postal survey to 3928 subjects, constituting a representative sample of the adult general population, followed by clinical examination in a selected group of subjects with CWP. CWP and FM were diagnosed according to ACR 1990. bromyalgia criteria. Health status was measured by SF-36 Health Survey. Results. Patients with CWP, CWP-M, and FM were found to present with more severe impairment of health status than the other two population groups. Several psychosocial factors, such as belonging to a lower socio-economic group, being an immigrant, living in a compromised housing area, having lower educational level, experiencing lower social support and having a family history of chronic pain, were associated with the populations with CWP and FM Conclusions. The spectrum of impact on health and association to background variables, with respect to a stricter de. nition of CWP, indicates that these factors are important to attend to in the understanding and management of CWP and FM.