The primary objective of this research study is to investigate the various causes of construction project delays in Dire Dawa Administration. In doing so, the researcher has employed dominantly quantitative research approach and the attributes are ranked in terms of their importance by using Relative Importance Index (RII). Moreover, both descriptive and explanatory (causal research) research designs via crosssectional survey are utilized for this study in. The data has been collected from both primary and secondary sources. Census method of inquiry is employed through distributing 102 a self-administered questionnaire to clients/government bureaus, contractors and consultants of large government owned construction projects. Relative Importance Index technique, one way ANOVA, ordinal logistic regression model and chisquare analysis are used for data analysis. The descriptive statistics result has revealed that delay in the manufacture of building materials (RII=0.81), delays in producing design (RII=0.8), low productivity level of labors (RII=0.8), insufficient work by the contractors (RII=0.78),equipment shortage (RII=0.78), material types and specification changes in the construction (RII=0.75), equipment breakdowns (RII=0.75), design engineer’s inability to understand the requirements of the owner (RII=0.75), discrepancies in project designs RII=0.74) delay in the delivery of materials on time (RII=0.74)are the top five perceived causes of large construction projects in Dire Dawa Administration. As a result, reconsideration should be due on project planning and designing of construction projects in order to find out the factors harming the possibility of timely completion of the projects in which stakeholders such as owners, consultants and contractors have clearly defined goals.