Variation is inevitable in construction projects due to the complex nature of the constructionrnindustry. It is common in all types of construction projects and it determines the time limitsrnand anticipated budget of the projects. Variation order is observed as one of the mostrnfrequently occurring issues in construction projects in Ethiopia. Like other regions of therncountry, construction projects in Addis Ababa are suffering from variation orders. Thesernvariations are known to impact various aspects of the projects. This study assessed the impactrnof variation orders on public building projects in Addis Ababa to reduce them. Thernobjectives of the study were firstly to determine the causes of variation orders; secondly tornidentify the impacts of variation orders; and lastly to recommend strategies to minimizernvariation orders. Through a comprehensive study of literature review, resulted inrnidentification of 38 common causes of variation orders, 15 impacts of variation orders and 15rnrecommended strategies to minimize variation orders and these variables were mapped inrnfrequency table. A desk study, interview and questionnaire survey were carried out to identifyrnthe causes of variation orders, their impacts on public building projects and to seekrnrecommendations to reduce them. The desk study conducted on five selected projects and therncauses of variation orders and their impacts on the projects were identified. Interviews werernmade with selected experienced public building project participants for expert opinion. Thernquestionnaire responses were analyzed using the relative index method. A triangulationrnmethod on the desk study, survey and the literatures was done to improve the validity of thernfindings from the study. The results indicated that design changes, incomplete contractrndocuments, and impediment in prompt decision making process were the most causes ofrnvariation orders. The results also showed that completion schedule delay, increase in projectrncost, and additional payments for contractor were the most impact of variation orders. Thernfindings also suggested the most recommended strategies to minimize variation orders. Thesernstrategies were to produce a concluding design and contract document, to complete drawingsrnat tender stage, and to supervise the works with experienced and dedicated supervisor tornminimize variation orders on public building projects. The study concluded based on thernfindings of the research and recommendations for further studies were forwarded to minimizernvariation orders.rnKey words: Variation order, cause, impact, public projects, Addis Ababa.