OBJECTIVES: To determine the well-being of physicians and nurses in hospital practice in Europe, and to identify interventions that hold promise for reducing adverse clinician outcomes and improving patient safety. DESIGN: Baseline cross-sectional survey of 2187 physicians and 6643 nurses practicing in 64 hospitals in six European countries participating in the EU-funded Magnet4Europe intervention to improve clinicians' well-being. SETTING: Acute general hospitals with 150 or more beds in six European countries: Belgium, England, Germany, Ireland, Sweden and Norway. PARTICIPANTS: Physicians and nurses with direct patient contact working in adult medical and surgical inpatient units, including intensive care and emergency departments. MAIN OUTCOME MEASURES: Burnout, job dissatisfaction, physical and mental health, intent to leave job, quality of care and patient safety and interventions clinicians believe would improve their well-being. RESULTS: Poor work/life balance (57% physicians, 40% nurses), intent to leave (29% physicians, 33% nurses) and high burnout (25% physicians, 26% nurses) were prevalent. Rates varied by hospitals within countries and between countries. Better work environments and staffing were associated with lower percentages of clinicians reporting unfavourable health indicators, quality of care and patient safety. The effect of a 1 IQR improvement in work environments was associated with 7.2% fewer physicians and 5.3% fewer nurses reporting high burnout, and 14.2% fewer physicians and 8.6% fewer nurses giving their hospital an unfavourable rating of quality of care. Improving nurse staffing levels (79% nurses) and reducing bureaucracy and red tape (44% physicians) were interventions clinicians reported would be most effective in improving their own well-being, whereas individual mental health interventions were less frequently prioritised. CONCLUSIONS: Burnout, mental health morbidities, job dissatisfaction and concerns about patient safety and care quality are prevalent among European hospital physicians and nurses. Interventions to improve hospital work environments and staffing are more important to clinicians than mental health interventions to improve personal resilience.