Referring to the needs of the community and since the government had launched a public housing program, public housing has become the focus in the housing market because home is an asset that everyone needs. There are some issues arise related to housing quality in public housing and make public housing program almost non-success. The housing defects is the biggest problem that occurs in public housing but efforts to reduce defects in public housing are still idle and not addressed due to lack of acknowledgement towards defects problem in public housing. Therefore, this research aims to investigate the causes of defects in public housing projects. The study implied a quantitative method that involves questionnaire survey. The questionnaires are distributes to contractors and developers who have an experience in public housing project in Klang Valley area. There were 136 valid responses were obtained from the questionnaire distribution to be analysed. All data are analysed using Statistical Package for Social Science version 22 (SPSS) software. The result reveals that poor workmanship, lack of supervision by superior, poor quality of material, poor quality of contractor and limited time of construction are the causes of defects in public housing. Therefore, it is hope that this study will raise awareness among construction team and government in order to reduce housing defect problem in Malaysia.