The efficiency of an IC engine is mainly depends on opening and closing of inlet and outlet valves. The valves are operated by cam shaft. So cam shaft must be free from defects to maintain proper combustion of a internal combustion engine. Thus we are focusing to reduce the defects and improving quality in the manufacturing process and operations of a cam shaft in manufacturing industry for different automotives. In camshaft manufacturing the considerable defects are material selection, changing their mechanical properties while machining, temperature defects, casting defects, tolerances and surface roughness. So manufactured cam shaft has to overcome above defects for safe operating of valves. Six Sigma is a business technique and a methodical philosophy utilization of which prompts achievement in benefit through quantum gain in item quality, consumer loyalty and efficiency. The goal was to diminish the quantity of deformities to as low as 3.4 parts per million chances. Methodology used: DMAIC is one of the tool of six sigma used to improve the process and also to find root causes for any problem to reduce the defects occuring in any industry. we are using DMAIC tool to reduce defects and improve quality. DMAIC stands for define, measure, analyze, improve, control.