The purpose of this paper is to carry out queuing analysis to examine multi-stage production line performance to facilitate more realistic resource planning. It is one of a few such studies to improve the performance of multiproduct multi-stage production lines. This work aims to help managers in improving the efficiency, effectiveness and selecting the most suitable policy for assembly systems. The paper adopts an analytical approach based on real life data from an international battery company producing battery covers for camera model EC-196. The battery production line consists of six independent workstations namely injection molding, first color spray, second color spray, ultra-violet (UV) station, assembly station and a packing workstation. The relevant data for each workstation was collected and the chi-squared goodness test was applied to determine the arriving and leaving distributions data of processing parts. Queuing analysis reported in this work provides a basis for estimating and analyzing production systems by measures such as utilization, percentage of idle workstation, number of batches in system, number of batches in queue, expected time spent in queue, and expected time spent in system. The comparison between results and standard data in the company showed an accuracy of 93.80%.