The main focus of this work was the Factors Affecting Cost of Construction Projects in Nigeria (A Case Study of Road and Building Firms in Nigeria). The objective of the study was to find out the factors affecting construction project cost in Akure a Southwest city in Nigeria and proffer solutions on how construction project cost can be minimized. The work involves cross-sectional survey of clients, consultants and contractors in construction-related establishments in Akure.It shows that there is a general agreement between all the parties in construction industry on the importance of factors affecting cost of construction projects in Nigeria; their view identified five most important factors which include: cost of material, economic instability, additional work, poor financial control on site, wrong method of estimation/inaccurate or poor estimation of original cost and poor project management.