Background: A model developed from a research review indicated that stress and job satisfaction in mental health nurses, among other variables is associated with inter-professional working and clinical leadership. Methods: the present study used a cross-sectional, correlational design aiming to test a model of associations between inter-professional working (collaboration between nurses and doctors as well as amongst nurses), clinical leadership (the team building skills of the head nurse), stress and job satisfaction in Greek registered mental health and assistant nurses. A sample of 85 (n=85) register mental health and assistant nurses working in six acute psychiatric wards was obtained. Data were collected using likert type questionnaire comprising six instruments selected for its high validity and reliability. Descriptive and inferential statistics were employed in analyzing the data. The statistical analysis was performed with SPSS v.15. Results: nurses, experienced moderate level of stress and overall were satisfied with their job. Collaboration between nurses and doctors was not found to be an influential factor in nurses’ stress level (r= -0.081;NS), or job satisfaction (r=0.069;NS). The significant findings was the influence of the team building skills of the head nurse in decreasing nurses’ stress (r=-0.445;p<0.01) and increasing job satisfaction (r=-0.418;p<0.05). In addition, stress was found to be negatively associated with job satisfaction (r=-0.453;p<0.01). However, the hypothesis that the team building skills of the head nurse would positively influence the quality of relationships amongst nurses was not supported due to the small and not statistically significant association found (r= 0.167;NS). Conclusions: the proposed model tested was not completely supported. However, the role of the head nurse has been found to be of paramount importance in reducing nurses’ stress and increasing nurses’ job satisfaction. Therefore, interventions on the first line management level must be taken place by hospital managers so as to train them to develop their leadership skills which are essential for the development of collaborative nursing team