The research paper aims to investigate and analyze the current situation of wastes elimination of the manufacturing firms in Gaza Strip and its important role for reducing the production cost; in addition it aims to promote lean thinking through studying the seven wastes that are targeted by the lean manufacturing philosophy. Wastes Relations Matrix (WRM) was implemented to analyze the effect of each waste on the other six wastes. The main findings are that lean manufacturing (wastes elimination) affects positively on reducing the production cost for the manufacturing business in Gaza strip.