The efficiency of a production system is mainly characterized by batch size and throughput. To ensure system efficiencies, batch size and throughput must be in conformity to achieve optimum utilization. This paper discusses the use of Queuing Network Theory to study the effect of batch size and throughput in optimizing resource utilization, particularly machine resources in a manufacturing system. A factory in the manufacturing industry performing assembly operations in its production lines was the focus of this study. The result of the study was that when batch size and throughput are increased, the utilization also increases proportionately. Bottleneck will occur when the capacity is not enough to meet the demand requirement.