OBJECTIVES: A predominant Health-Related Quality of Life Model (described by Wilson and Cleary in 1995) proposes a sequential relationship from biological and physiological variables to perceived health and overall quality of life.  We assessed the extent to which disability mediates the association between mental and physical conditions with perceived health. METHODS: Data come from the WHO World Mental Health (WMH) Surveys carried out in 22 countries worldwide (n = 51,344 respondents, 72.0% response rate). We assessed 9 common mental disorders with the WHO Composite International Diagnostic Interview v3.0 (CIDI), and 10 chronic physical with a checklist. Perceived health (PH) in the previous 30 days was assessed using a numerical scale (from 0, worst, to 100, best). Disability was assessed using a modified WHO Disability Assessment Schedule 2.0 (WHODAS). Path analysis and multigroup techniques were used to estimate total effects of physical and mental conditions on perceived health PH and their separate direct and indirect (through the latent and observed WHODAS dimensions) effects. RESULTS: