A Dissertation Submitted in Partial Fulfillment of the Requirements for the Award of the Degree of Master of Science in Human Resource Management (MSc-HRM) of Mzumbe University.This study intended to assess the impact of employee turnover on organization performance at Barclays bank Tanzania Limited in Dar-es-Salaam region. The study was conducted with the following objectives: To assess the impact of employee turnover on organization performance in Barclays bank Tanzania Limited; investigate the causes of staff turnover in Barclays bank Tanzania Limited and finally recommend strategies that can be used to reduce the high level of employee Turnover in Barclays bank Tanzania Limited Data were collected through Questionnaires, Interviews and Documentary Review. Questionnaires were open-ended questions, which allowed individuals to express their views concerning the impact of employee turnover on organization performance at Barclays bank Tanzania Limited in Dar-es-Salaam region. Interviews were conducted on the basis of predetermined interview guide. In addition, when an organisation loses a critical employee, there is negative impact on innovation, consistency in providing service to guests may be jeopardized and major delays in the delivery of services to customers may occur. The research design used in this study was the quantitative approach, which allowed the researcher to use structured questionnaires when collecting data. The targeted population was the employees across Dar es salaam branches which consisted a sample size of 100 employees. Simple random sampling was used in this research. The study finding suggests that salary is among the primary cause of staff turnover in the Barclays bank Tanzania Limited. The findings highlighted that high staff turnover increases work load to the present employees in Barclays bank Tanzania Limited. The study finding also showed that staff turnover causes reduction in effective service delivery to the customers and reflects poorly on the image of the Barclays bank Tanzania Limited. Other findings suggested that unhealthy working relationship may also be the cause of staff turnover in Barclays bank Tanzania Limited. The recommendations highlighted that top management should pay a marketable salary to employees and the employees must be rewarded if they have achieved their goals. Top management should also develop opportunities for career advancement in Barclays bank Tanzania Limited. Top management should involve employees when they make decisions that will affect them in Barclays bank Tanzania Limited. The study concludes with direction for future research