This paper describes the application of computer simulation for the purpose of analysis of an assembly line and the subsequent proposal of changes to increase productivity. Tecnomatix Plant Simulation software was used for modeling, simulations, and analyses. Based on simulations and analyses of the original state, the bottlenecks of the line were identified, and improvement measures were proposed. The simulation model was adjusted, and the new state of the line was simulated. Based on the new simulation, it was proven that the proposed improvement would help in increasing the productivity of the assembly line. Computer simulation, in addition to verifying the production process itself, enables the optimal setting of the assembly line without interfering with the production itself.