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.The study aims at evaluating performance appraisal methods and use of results at both public (TANESCO) and private (Symbion) organizations. The objectives of the study is to compare performance appraisal methods in both public and private organizations, to determine suitability and performance of various types of performance appraisal methods, to determine employers and employees' level of satisfaction regarding the said appraisal methods, and to explore ways to harmonize the use of various types of performance appraisal methods. The study used interview andsurvey to collectdata from a sample of 50 respondents from TANESCO and 50 respondents from Symbion Power. The study revealed that the performance appraisal results have benefits in a number of ways including informing the employees' developmentplans, for instance, through identification of necessary training requirements, giving enough opportunities to employees by recognizing their talent and giving them more responsibilities, and identifying poor performing employees and put them under a performance improvement plan so that they can be effectively guided and groomed to become good performers. It is also instrumental in identifying any other reasons for nonperformance of an employee, like non-availability of tools to perform their job or other external factors and remove those obstacles so that employees are in a position to perform their job well. The absence of performance management has contributed to the high rate of business failures in the public and private sector. The study recommends that the public and private organizations should make sure that performance elements and standards should be measurable, understandable, verifiable, equitable, and achievable. Effective performance management system requires time and resources and management is supposed to act upon the outcomes of the performance management process.