This work aimed to determine ways of managing supplier relationships to improve public procurement performance while conforming to legal and procedural framework for public sector procurement. Supplier relationship management is one of the most important aspects of supply chain management. The advent of the Public Procurement Act, 2003 (Act 12) in Tanzania addresses so many procurement issues but does not address supplier relationship management issues so as to achieve a long term benefit for the organization that will bring a win-win approach for the benefit of the organization. The study set use of public entity TANESCO institution as a case study to determine how supplier relationships manage vis-à-vis procurement regulations to achieve procurement performance. The findings reveal that TANESCO follow accept strategies of supplier relationship management in extent literature in order to ensure value for money and improve procurement performance. The Challenges of Managing Buyer-Supplier Relationship in Public Organization will carry out the overall objective of the study. Managing Buyer-Supplier Relationship in public organization with particular focus of TANESCO Mwanza City, the researcher aimed at determining the communication means on the relationship between Buyer and Supplier in the whole process of procurement. To investigate the lead time of affecting Buyer-Supplier Relationship in the whole process of procurement and to determine how does Buyer-Supplier Relationship contribute to business improvement. The study involves a case study where the researcher will collect data from TANESCO staff, employees in procurement department, Suppliers and Employees of Accounts department. Questionnaires, interviews and documentary review were the methods for analyze and collect data.