Cost estimation of construction projects is the basis for project life cycle cost management. The accuracy of project cost estimates depends on many factors, such as: Labor and equipment prices and availability of production rates, availability of material prices, accuracy of bid documents provided by project's owner, and market conditions. The price of construction materials accounts for a large proportion of the total project cost. Therefore, the availability of material prices is one of the most important factors affecting the accuracy of project cost estimates. When estimating costs at the bidding stage, a variety of material price sources can be used, such as: Catalogs from suppliers and manufacturers, surveys, historical data, price lists, and price bulletins from government or private organizations. This paper evaluates the availability of cost data in Egypt for detailed construction cost estimates and the reliability of the available data. The paper highlighted that there are two formal references for construction material price bulletins in Egypt (CAPMAS Central Agency for Public Mobilization and Statistics, and MHUC Ministry of Housing, Utilities & Urban Communities) which are issued on a monthly basis. The evaluation of the data availability and reliability in the formal bulletins were conducted using a real contractor's tendering estimate documents as case study by comparing to the cost estimates based on these bulletins. The results show that the available material prices provided by MHUC represents about 78% of total material cost in the case study, while the CAPMAS available data represents only about 45%. This study also highlighted the high level of accuracy of both bulletins' material prices compared with actual market prices in terms of civil and architecture materials and low accuracy for electro-mechanical materials.