Projects failure is a common phenomenon in the current society. The construction industry isrnone of the most practical examples of project based industries. Amongst the multitudernconstruction projects here in Addis Ababa, one is the Housing Development Project with thernmain objective of addressing the housing needs of the city and other socio-economic goals.rnHowever, according to the reports the Addis Ababa Housing Development andrnAdministration Bureau, only 180,000 houses have been delivered to the beneficiaries sincernthe establishment of the project office in 2005, that means it has failed to achieve itsrnobjectives as of the conventional success metrics. Due to this, it becomes critical tornunderstand the most significant causes that hindered the project to succeed. Hence, this studyrnis aimed to identify the most significant project failure causes of the office, the knowhow andrnpractice of PM theories and concepts, and the ten PMKAs, of course, based on thernperceptions of the practitioners in the project execution.rnThis case study is an exploratory type and used a mixed method approach research designrnwith a multi-level cluster sampling techniques. The data was collected using documentsrnreviews, semi-structured interview and questionnaires; and the analysis was made usingrnthematic analysis and SPSS tools sequentially for qualitative and quantitative daternconsecutively.rnManpower, Planning and Procurement related causes were found to be most significant, andrnthe assessment revealed that the PM theories and the ten PMKAs neither known well norrnpracticed in the project office. Eventually an attempt was made to relate the identified mostrnsignificant causes with the PMKAs. As the most significant project failure causes wererndirectly related with the PMKAs like PMI, PHRM and PPM, a more intense ProjectrnManagement expertise and practices were recommended for the improvement of the projectrnofficeâ€™s performance.