Assefa, Abraham (PhD)Mamuye, Endale2018-07-032023-11-112018-07-032023-11-112016-12http://etd.aau.edu.et/handle/12345678/5570Delay is the most frequent problem in the construction industry particularly in developing countries like Ethiopia. However, it can be better managed when the causes are identified and action is taken by the concerned bodies. The main objective of this research is to identify the major causes to the delay in the construction of 40/60 saving houses project in Addis Ababa. Overall, 80 respondents from client, consultants and contractors participated in the survey and identified 10 major causes of delay from a list of 45 common causes of delay based on the relative importance index (RII). The ten major causes of delay in the construction of 40/60 saving houses project were late material supply, financial difficulties faced by the contractor, problem of electric supply, problem of water supply, equipment unavailability, delayed payments to contractors, poor site management, ineffective planning and scheduling, late design review and approval, and slowness in decision making process. The results of the case studies showed that late material supply was mainly caused by the client due to financial shortage, time taking material procurement process, unfair distribution of material, shortage of transport facilities, scarcity of material in the market etc. Financial difficulty faced by the contractors was caused by both the contractors and the client due to the contractors’ poor financial management, and delayed payments to contractors. Problem of electric supply was caused by both the client and the contractors due to frequent power interruption, late maintenance, unsafe construction, unavailability of high capacity stand by generators etc. Furthermore, the impacts of the major causes of delay were time overrun and cost overrun to the client and the contractors. Key words: Delay, Questionnaire Survey, Relative Importance Index, Major Causes of Delay, Case Studies, Sources of Delay, Reasons, ImpactsenDelayQuestionnaire SurveyRelative Importance IndexMajor Causes of DelayCase StudiesSources of DelayReasonsImpactsThesis