Currently, most public building construction projects in Addis Ababa suffer delays, underperformance, and cost overrun due to a number of reasons. One of the reasons is the poor practice of cost controlling of projects that is leading to dispute and termination of contracts among stakeholders. This study investigated the cost control practicein building construction projects: the case of public projects in Addis Ababa, which are being administered by the Ministry of Urban Development and Construction (MUDC). The objectives of the study were to assess the current cost controlling practices & techniques; determine best practices & benchmarking tools and techniques; identify factors influencing cost control; identify methods of construction cost minimization and develop cost controlling tool which can be applied in the construction industry. The methodology used for data collection included literature review, questionnaires, and interviews. The interviews were made with selected experienced public building construction participants to capture expert opinions. To analyze the data percentage method and Likert scale analysis using relative importance index (RII) are used to examine the results from the questionnaire and findings are presented in charts and tables. The research result indicated that majorities of the respondents have well understood and awareness about the cost control in constructionindustry. However, the practice is not effective as per their level understanding. The majority ofthe clients and consultants apply forecast/estimate at completion and budget at completion techniques, while most contractors apply overall profit and loss of the contract using MS-excel softwarepackage. However, the finding indicated the majorities are not effective on cost control techniques. Whereas, respondents’ result obtained from the questionnaire indicated applying earned valuemanagement technique was very effective. The top five ranked factors influencing cost controlin public building construction projects in Addis Ababa are market conditions /inflation, construction material cost, change of currency/ exchange rate, design change, and dependency on imported materials. Efficiently scheduling labor, materials, and equipment, good work planning, taking correctiveactions to minimize cost overruns, inspecting and evaluating the actual and budgeted cost of work,and minimizing rework through timely quality control were major top-five ranked methods of construction cost minimization in public building construction projects. Finally, after an exhaustive study of the literatures and analyzing the research outcome, the study has developed cost control tool using EVM that can support public building construction stakeholders to control project costs during the construction process. Key words: Cost, cost Control, Construction Project, Public Building project, building projects