In this century, manufacturing productivity is one of the most significant element that determines the position of a manufacturing company among well entrenched competitors. The performance and efficiency of an assembly line are relatively significant as they contribute immensely the productivity. In this study, a case study of lamp production assembly line was conducted in order to develop improved version of assembly line with greater performance and efficiency. This study was carried out by theoretically analyzing the various studies conducted previously on assembly line optimization. Process and time study of the current assembly line were conducted. Sequel to these data collected, root cause analysis was conducted to identify the cause of the problem in the assembly lines. FlexSim was used to simulate the current assembly line and the performance result was generated. The result was analyzed using lean production review. A Karakuri system was implemented to eliminate the non-value added operations. Subsequently, assembly line balancing was applied by using 4 different heuristics methods. As a result, 4 versions of improved assembly line were developed. Furthermore, simulations of the 4 versions of improved assembly line were conducted and the result of performance was generated. Lastly, a comparison between the current assembly line and 4 versions of improved assembly line was made and the most productive assembly line was selected as the proposed assembly line.