Cost management practices have remained a vital aspect of project management functions. Despite the efforts of project management, construction projects are still being delivered above budget, with schedule overrun, poor quality and amongst other problems. Poor cost management approaches have been blamed for these problems. Effective cost management improves project performance and the strategic performance of construction organisations. This study aims to assess the role of cost management practice on construction firms' strategic performance in Nigeria. The objectives of the study are to determine the benefits of cost management of the project on the competitive position of construction firms, and the factors influencing cost management strategies of construction firms. This study adopted a well-structured questionnaire administered to construction professionals via electronic means and using snowball sampling technique in the six states of the south-south geopolitical zone of Nigeria. With a response rate of 65.48% and a reliability of index of over 0.70, the gathered data were analysed using frequency, percentage, and relative importance index (RII). It was found that major factors influencing construction cost management are; experience and competence of the project managers, weak management support and control, poor project communications, external economic environment, and lack of use of project management tools (technology). Also, effective cost management was found to play a critical role in the strategic performance of construction organisations; with most benefits being in the areas of waste and expenses reduction, improves operational efficiency need, helps to predict future expenses, ensures procurement effectiveness, and improve profit maximization. Project managers should continuously upgrade their skills for effective cost management to boost the strategic competitive position of their firms.