Background: Determination of unit cost using the ABC Costing Model at Private Hospitals in collaboration with the National Health Insurance is expected to conduct an evaluation, analysis of tariff policies whether it has provided benefits or vice versa as an example is the X-ray examination at Private Hospitals Class C in Bantul. The activity of calculating cost using the unit cost calculation of the Activity-Based Cost model has never been done by radiology units, especially the chest X-ray with the number of examinations more than other X-rays. Determination of chest X-ray cost still uses traditional model calculations by including cost components: raw material prices, film prices of public and private hospitals competitor, film uses for one year, exposure factors of x-ray, medical equipment used, infrastructure of medical devices, specialist doctors. The chest X-ray examination has increased every year and uses high-cost digital X-ray printers. Increased examinations in 2015 there were 5,960 examinations then continued in 2016 with 7,925 examinations and in 2017 there were 7,980 examinations but the increasing number of examinations was not supported with correct tariff calculation to date and traditional calculation model is still the hospital’s reference in determining cost Method: Using descriptive research with quantitative descriptive approach with the aim to get a describe the unit cost related with examination of the chest X-ray, research design using primary data through interviews, observations and using secondary data to identify cost related with the chest Xray that uses cost calculations based on activities Result: Chest X-ray cost at Private Hospitals Class C in Bantul using the Activity-Based Costing calculation model, get a unit cost of Rp. 106.489 The nominal value of the cost is greater than the real cost of the hospital’s chest X-ray with a difference of Rp. 7.989 The nominal cost of the chest x-ray unit with the calculation of the Activity-Based Costing (ABC) method is smaller when compared to the outpatient cost for Private Hospitals Type C in the INA-CBG’s program, with a difference of Rp. 8.311 Conclusion: Result calculation chest X-Ray cost using the ABC Costing at Private Hospital Class C in Bantul obtained higher cost when compared to hospital real cost and lower than INA-CBG’s Claims