The purpose of this study was to test an expanded model of Rosabeth Moss Kanter's Structural Theory of Organizational Behaviour (Kanter 1977; Laschinger, Finegan, Shamian and Wilk 2001) by examining the relationship between nurses' empowerment and their perceptions of effort-reward imbalance (Siegrist 1996). A sample of 112 staff nurses employed in teaching hospitals in Ontario participated in this study (58% return rate). A descriptive correlational survey design was used to collect data by eLiciting responses to five self-report instruments: the Conditions of Work Effectiveness II, the Job Activities Scale II, and the Organizational Relationships Scale II (Laschinger, Finegan, Shamian and Wilk 2001), the Effort-Reward Imbalance (ERI) scale (Siegrist and Peter 1999a) and a demographic questionnaire. Staff nurses were only moderately empowered, and 24.1% perceived their work to have more efforts than rewards, according to Siegrist's guidelines.