An electric cable is a medium that is in the form of a conductor and insulator to deliver electric current from the area of origin to the destination. The quality of a cable is very much determined by the medium of transmission, the delivery material can be copper or aluminum. PT XYZ Tbk is one of the companies engaged in the electrical cable that produces bare conductors. One type of product produced by PT XYZ Tbk is medium voltage cable. Medium voltage cable is a type of cable that can deliver electricity to 35 kV. But among various types of medium voltage cables, NFA2XSY-T products have the highest fail rate among other types of medium voltage cable, which makes the frequency of rework and repair of these products higher. Based on historical data for three months, from June to August 2018, it is 21%, while the company’s target is 1%. Therefore, in this study a quality improvement was carried out to minimize the level of defects with the six sigma method with the Define Measure Analyze step. Improve Control. In the Define stage, it is done by identifying the type of defect, step Measure evaluates the stability of the process and identifies the quality costs associated with defects that occur, in the Analize stage, by analyzing the causes of the dominant defect, in the Improve phase, improvements are made by making standard operating procedures, then at the control stage, it is attempted to compare between DPMO and Sigma Level before and after implementation. Based on data processing obtained DPMO of 77,585, and Sigma Level of 2.9, with total quality costs of Rp. 21,260,413 / day, after implementation DPMO was obtained at 55,556 and Sigma level of 3.9 with a total cost of Rp. 14,049,757 / day