Objective to explore the sources and levels of stress at work and work ability among Croatian midwives. Background midwives are subjected to multiple stressors. Among health-care professionals, psychological distress for a prolonged period of time has negative effects on the worker's health, work ability and quality of patient care. ‘Work ability’ is a term describing a worker's resources related to physical, mental and social demands at work. As a measure of work ability in midwifery, the Work Ability Index (WAI) is considered to be a very predictive instrument; midwives with a poor WAI score usually leave their current job within five years. Setting university hospitals in Zagreb, Croatia. Design cross-sectional design survey. Participants 300 health-care workers (105 qualified midwives and 195 paediatric nurses) were invited to complete the questionnaire. The total response rate was 53% (158/300). The sample included 14.7% of all hospital-based midwives in Zagreb hospitals. Methods the Occupational Stress Assessment Questionnaire (OSAQ) for health-care workers and the WAI questionnaire. Findings over three-quarters of the midwives (46/60, 76.7%) believed that their job was stressful, and considered that insufficient work resources caused the most stress. More than half of the midwives associated an insufficient number of coworkers, unexpected situations, inadequate income, night work, incurable patients and poor organisation at work with a high level of stress. The perceived specific stressors differed between midwives and paediatric nurses in the same hospital. Insufficient work resources and poor organisation at work were more common stressors among midwives than paediatric nurses ( p<0.05). Midwives and nurses differed significantly with respect to age ( p=0.002). Midwives were younger and had spent fewer years working in their current workplace compared with paediatric nurses ( p<0.001). Also, midwives had a lower level of education than paediatric nurses ( p=0.044). The mean WAI score for midwives was 40.0 [95% confidence interval (CI) 38.4–41.4], compared with 37.5 (95% CI 36.4–38.8) for paediatric nurses, both indicating good work ability. After adjusting for age, the difference in WAI score between the groups of workers was not significant. Conclusions Croatian midwives experienced work-related stress due to: insufficient work resourses, insufficient number of coworkers, poor organisation at work, communication with superiors and emotional work. Midwives’ work ability in relation to the demands of their job was good. These results confirmed that the WAI score decreases significantly with age. Implications for practice hospital management needs to improve organisational factors and resources, as well as midwives’ education and position in the health-care system.