ABSTRACT This study dealt with the investigation of the Causes of Organizational Conflicts and Their Effects on Work Performance at Sekou-Toure regional hospital in Mwanza. Specific objectives of the study were to determine factors causing Organizational conflicts at Sekou-Toure regional hospital in Mwanza and to establish the relationship between Organizational Conflict and Work Performance at Sekou-Toure regional hospital in Mwanza. An overarching question for the study was; what are the Causes of Organizational Conflicts and Their Effects on Work Performance? A sample of 186 respondents was used in the study. The primary data were collected using questionnaires and interviews, secondary data were collected through a review of Sekou-Toure documents like the employees’ meeting minutes. Statistical package for social science (SPSS) was used to analyze quantitative data. The findings reveal that there are conflicts at the research area between subordinates and their supervisors and also among the peer workers. Causes of the conflicts including subjectivity of some leaders that was noticed in the area of distribution of opportunities like seminars, failure to observe boundary of operation and differences in priorities between leaders and other workers. The study recommends having all administrators at Sekou-Toure regional hospital given training on the leadership skills to make them function accordingly reducing or removing subjectivity so that they treat all workers equally to enhance interpersonal relationships among the employees, hence creating a supportive working environment