This study aims to investigate the extent of aggression exposure and the effects of exposure on the psychological health of nursing staff in hospitals. A survey was conducted using a randomised sample of 314 nurses. The majority (n=195, 62.1%) of staff surveyed had been exposed to aggressive patients at least once within 4 weeks prior to survey. Nearly 40% of exposed staff had frequent exposures. Results on the General Health Questionnaire (GHQ) and Beck's Depression Inventory-Revised (BDI-R) suggested that nearly 40% of staff experienced psychological distress, while nearly 10% experienced moderate to severe depression. After adjusting for potential confounders, results of the logistic analyses indicated that frequent exposure to aggressive patients is detrimental to the mental health of nurses. These findings have implications for the provision of support and other related services for nursing staff.