This research focuses on an important sector of the national economy sectors, which is the industrial sector and, especially engineering industry. This research aims to explain the importance of using research operations methods in the process of decision- making, especially in choosing optimal product mix in engineering companies in the Syrian coast. These methods play an essential role in making scientific and logical decisions to solve problems which face decision-makers in these companies. They provide a set of alternatives that help decision-makers on choosing the best alternative among available alternatives set to solve the problem that face them. This positively influences the work of these companies, which, in turn, positively influences their role in industry and national economy. The researcher found to following results: - Using research operations methods requires a definition of these methods, availability of proper financial support, suitable work nature, availability of required data and availability of computers. - Using research operations methods helps to improve the decision-making process in choosing optimal product mix through decreasing production costs, optimal using of available resources, optimal investment of production power.