The book "The Effect of Critical Factors on Construction Projects Performance" is a comprehensive study of the critical factors that influence the performance of construction projects. It is based on a master's thesis in construction management written at the Sudan University of Science and Technology. Under the supervision of the experienced engineer Dr. Mohamed Ibrahim Yousif, the work analyzes the challenges faced by the construction industry worldwide and highlights the various causes that can jeopardize project progress. The book offers a detailed discussion of the life cycles of construction projects and identifies the key factors that affect their success or failure. It is aimed at professionals and students in the field of construction and engineering who wish to gain a deeper understanding of the dynamics of construction projects and their performance factors.