Background: People with respiratory conditions are a 'high-risk' group for H1N1 pandemic swine influenza ('swine flu'), hence they and their families may have information needs, worries and concerns regarding the condition. Health-related behaviours, including vaccination, are recommended during the pandemic; understanding uptake of these is important. Objectives: To explore and compare information needs, worries and concerns, and health-related behaviours regarding swine flu in people with respiratory conditions and their family members. Methods: Mixed-methods study - cross-sectional survey (253 patients, 101 family members); one-to-one interviews (13 patients, seven family members) and focus groups (n = three groups, 30 participants). Data collected October 2009-January 2010 from hospital chest clinics (n = 7) and patient support groups (n = 10) in North West England. Results: Most patients (P) and family members (FM) wanted more information (n = 158, 62.5% P; n = 55, 54.4% FM), but few felt completely uninformed (n = 15, 5.9% P; n = 3, 3.0% FM). Most had already received information about swine flu (n = 187, 73.9% P; n = 78, 77.2% FM), mainly via a leaflet delivered to their home (n = 125, 49.4% P; n = 55, 54.5% FM). Information received was considered helpful (n = 154, 60.9% P; n = 77, 72.6% FM), but many wanted more condition specific information (n = 141, 55.7% P; n = 60, 59.4% FM). More patients were worried (n = 147, 58.3%) than not worried (n = 99, 39.3%) about swine flu. FM were less often concerned about personal risk (n = 47, 46.6% worried) than about risk to patients (n = 76, 77.6%). Two-thirds (n = 161, 63.6% P; 65, 65.6% FM) incorrectly believed patients had increased risk of developing swine flu, but most (n = 204, 81.0% P; 89, 89.9% FM) correctly identified patients' greater risk of developing complications. Commonly adopted preventative measures were more frequent hand-washing (107, 42.8% P; 38, 37.6% FM) and greater use of sanitizing hand gel (n = 100, 40.5% P; 37, 36.6% FM). In total, 212 patients (83.8%) and 69 family members (68.3%) were very/fairly likely to take up swine flu vaccination. Qualitative data mirrored survey findings. Conclusions: Participants were generally wellinformed about swine flu, but more targeted information would have been welcomed. Participants were not highly anxious about swine flu, but did recognise risks for patients. Behaviour change was modest, but in line with recommendations. Vaccination intent was high. Study registration: The study has been registered as REC/IRAS (Ref 09/H1015/76) and NIHR CSP (Ref 32483). © 2010 Queen's Printer and Controller of HMSO.