According to previous studies, temperament predicts a large share of the variance in job stress. It may be necessary for mental health practitioners to offer intervention strategies in accordance with individual temperament. To investigate the relationship between job stress and temperament among nurses in a general hospital and to provide insight into personality traits influencing their mental or physical health. A questionnaire survey of nurses in a general hospital. Work stress was measured using the Japanese version of the Effort-Reward Imbalance (ERI) scale. Temperament was assessed by a Japanese version of Temperament Evaluation of Memphis, Pisa, Paris and San Diego-Autoquestionnaire (TEMPS-A). Hierarchical multiple regression analysis was used to determine the independent contribution of temperament to effort-reward ratio and over-commitment. Response rate was 48% (326/685). Temperament predicted part of the variance of the four ERI ratios (effort-reward ratio 26%; effort-esteem ratio 27%; effort-promotion ratio 26%; and effort-security ratio 18%) and also of over-commitment (38%). Depressive temperament influenced all four ERI ratios and over-commitment. Anxious temperament influenced only over-commitment. Nurses with depressive or anxious temperaments should be identified, monitored for signs of job stress and offered interventions to prevent adverse physical and mental effects.