Lean manufacturing has received a great deal of attention in its application to manufacturing companies. It is a set of tools and methodologies that aims for increased productivity; cycle time reduction and continuous elimination of all waste in the production process. The Lean manufacturing technique - Kaizen is internationally acknowledged as a method of continuous improvement, through small steps, of the economical results of companies. In this paper a case study is presented in which bottlenecks are identified in the assembly shop of the tractor manufacturing automobile company due to which the productivity was low. Thus, the implementation of lean manufacturing kaizen technique results in the removal of bottlenecks by reducing cycle time, increasing the productivity and eliminating all kinds of waste.