Waste is an inherent element in the construction process, which hampers project improvement severely. Lean construction is a given name of an approach that helps in improving project value in terms of both time and cost by eliminating non-value added activities (waste) and by improving the percentage of value added activities in whole construction process. Gulf construction industry is playing an important role in the economic developments of Middle East region. Because of high infrastructure and housing demands in recent time, construction sector is being considered as the major contributor in GDP of this region. On contrast to these developments, this sector is facing problems in acting role on its full swing because of different factors such as low performances, inefficiencies or large variability which are affecting project performance severely in terms of time and cost. The goal of this study is to assess the effects of construction wastes on project performances using lean construction principles.