BACKGROUND The mental health of nurses is an important issue. OBJECTIVE To examine relationships between effort-reward imbalance (ERI) and depression and anxiety in nurses of a Japanese general hospital. METHODS A self-report survey was conducted among 406 nurses. Work stress was measured using a Japanese version of the ERI scale. Depression and anxiety were assessed by an item of the QOL-26. Logistic regression analysis was used to determine the independent contribution of the effort-reward ratios or overcommitment to the depressive state. RESULTS Both higher effort-money ratio and higher overcommitment significantly correlated with the depressive state (OR: 2.75; 95% CI: 1.34-5.66 and OR: 1.27; 95% CI: 1.15-1.41, respectively). CONCLUSIONS These findings suggest that in addition to effort-money ratio, overcommitment at work is an especially important issue that may be able to be managed in health promotion services for nurses in general hospitals.