The purposes of this research are to analyze the comparison of cost of goods manufacture by usingtraditional and ABC methods, and to analyze the advantage of their application in calculating the cost ofgoods manufacture to increase the competitive advantage at PT INKA (Persero) Madiun. This research is aqualitative research with descriptive method. The analysis result shows that PT INKA (Persero) Madiuncalculates direct hours of the employees as the basis of determining the overhead cost of each product. Byusing traditional method, the cost of goods manufactures of Economy Class Train (K3) AC is IDR 2,522,926,538,Economy Class Train (K3) Green Car is IDR 363,126,214, and Economy Class Train (KMP3) AC is IDR3,145,136,617. Meanwhile, the calculation using ABC method shows that cost of goods manufacture of EconomyClass Train (K3) AC, Economy Class Train (K3) Green Car and Economy Class Train (KMP3) AC are IDR2,727,987,080, IDR 360,001,314, and IDR 3,383,215,414. So, for the comparison, traditional method determinelower cost of goods manufacture from ABC method (undercosted) for two products, that are Economy ClassTrain (K3) AC and Economy Class Train (KMP3) AC. While in Economy Class Train (K3) Green Car, traditionalmethod determines higher cost of goods manufacture compare to the calculation of ABC method (overcosted).This results recomend to the important of implementing ABC method in calculating cost of goods manufacturewhich give more accurately calculation to develop competitive advantage, that help the management inmaking decision of determining the price, determining the strategy of cost leadership, and implementing theActivity Based Management (ABM).