This paper reports an investigation of the productivity problems through a structured questionnaire survey of 41 project managers working on construction building projects in Great Cairo. The projects are divided into two main categories residential building projects and nonresidential building projects. Respondents were required to rate how thirty factors affecting labor productivity with respect to importance and frequency of occurrence. The overall severity of productivity problems was then established using the product of these importance and frequency responses. The ten most significant problems affecting labor productivity were identified as length of work day, equipment breakdown, lack of materials, lack of proper equipments, lack of proper tools, inadequate supervision skill, material type, large volume of work, quality required, and work complexity. The reliability of those thirty factors was tested using Cronbach's Alpha measurement and the results indicated that the thirty factors studied are reliable for future use in assessing the severity of the productivity problem.