This research paper is intended to provide the clients, project managers, designers, and contractors with necessary information needed to better manage the quality of building construction projects. The paper reports the findings of a research study which was undertaken to determine the underlying factors affecting the quality of building construction projects. This study was conducted in a detailed manner through questionnaire and collecting the responses from various construction projects. Thirty five factors have been identified as critical factors of quality and based on this questionnaire were framed for survey. Detailed questionnaires were floated to quality Engineers, Site Engineers, Contractors and the responses were collected. It gives a background of the critical factors, Problems defining relative importance and constraints of the construction projects. Some factors were identified as critical factors of quality and responses were manually analyzed by using the software OriginPro.