Nursing staff are exposed to stressful work load which in turn is associated with poor physical and psychological health, sickness absence and job exit. The effort-reward imbalance (ERI) model is a validated approach to measure chronic psychosocial work stress by identifying nonreciprocity between occupational efforts spent and rewards received, and has been found to predict poor health. The aim of this cross-sectional study (n = 367 nurses and nurses aides) was first to test the psychometric properties of the Danish questionnaire measuring ERI, and secondly to analyse whether psychosocial work stress is associated with six indicators of poor self-rated health. Results derived from confirmatory factor analysis indicate satisfying psychometric properties. Elevated risks of poor self-rated health (odds ratios varying from 1.92 to 4.76) are observed in nursing staff characterized by high effort in combination with low reward. Effects are enhanced in those respondents who additionally exhibit a high level of work-related overcommitment. In conclusion, despite methodological limitations, this study contributes to the validation of the ERI questionnaire in Danish language. Furthermore, by documenting associations with poor self-rated health, it supports efforts of theory-guided prevention of work stress in health care professions.