Motivation is a key factor that promotes construction productivity. In construction domain, manpower plays a major role in the success of the projects, as it relies on their efficient performance. Therefore, it is an essential issue to study the factors that motivate manpower in construction projects. The objectives of this paper are to identify the key manpower motivation factors in the Egyptian construction projects and finally identify which motivation theory fits the culture of the Egyptian manpower. From the literature review, 28 factors were identified and these factors are reduced to 14 factors after brain storming sessions. The 14 factors were grouped into four categories: management, development opportunities, financial, and work climate, and also classified into intrinsic and extrinsic factors. A questionnaire was designed to collect data from engineers and labors. From data analysis the results revealed that the five key factors affecting engineers and labor represented 40% and 38% of the total factors respectively. Engineers and labors both have four key factors in common: good salary, bonuses, achievement, and recognition. But, the fifth factor is advancement and good supervision respectively. by taking into account the key motivation factors ranking, the Egyptian manpower is more relevant to the Herzberg's motivation theory, and more related to extrinsic factors. This finding can be used to assess construction manpower's motivation, which will be helpful in the development of human resource policies and, as a result, productivity enhances.