OBJECTIVES: Understanding and identifying impaired QoL is now recognised as an important component of asthma management.To assess QoL and factors influencing it, in asthmatic patients in Spain. METHODS: Observational, multicenter study was carried out in 40 Spanish pneumology units. Asthma diagnosed patients (according to GINA) aged ≥18 were enrolled. Disease severity and treatment information were investigator-reported, and socio-demographic data, symptoms, and QoL (self administered Mini Asthma Quality of Life Questionnaire ,Mini AQLQ) were patient-reported.  Optimal scaling methods for multivariate categorical data were conducted. RESULTS: A total of 536 patients were studied (mean age 54 years; 65% female). Significant differences in Mini-AQLQ total scores were observed by disease severity according to GINA: 4.3 (SD 1.3) for severe persistent, 4.9 (SD1.2) for moderate persistent, 5.4 (SD 1.0) for mild persistent and 5.7 (SD1.0) for intermittent patients (p<0.0001). As per the final multivariate model (with MiniAQLQ total score as dependent variable and after adjusting for all significant variables in the bivariate analysis), reported QoL was better for patients from Northern and Central Spain as compared with those from the South and the East (p<0.0001), students and employed patients as compared with housewives and unemployed (p=0.001), for those who had received information about the disease compared with those who did not (p=0.004), for those with milder daytime symptoms (p=0.001) and for patients with higher education (p=0.021). CONCLUSIONS: Modifiable factors such as symptom control and adequate information about asthma can have a significant effect on patients' QoL.