Revolutionary changes has been done in many aspects in businesses such as production methods, product supply, product differentiation and delivery of products to the customers with the development of technology. This situation forces businesses to work with more accurate cost methods. By using TDABC (Time-Driven Activity Based Costing), managers not only distributes the costs more accurately and in a shorter time but also calculates idle capacity, which is not taken into consideration in traditional cost methods. Therefore, this method enables managers to take quick and effective decisions. According to the TDABC, idle capacity costs are classified as running expenses, not production costs. Thus, product costs can be calculated more accurately. Although TDABC distributes costs accurately to the activities, it cannot measure the efficiency of the activities in accordance with capacities. That’s why, theory of constraints also should be used together with TDABC method in order to measure the efficiency of each activity. Since all the data that are going to be used at the implementation part of integrating the TDABC and theory of constraints is so spesific, a case study method was chosen as a research method. First, an interview was conducted with the logistics cargo business managers for having an insight how they organize their work processes. This is how activities of the business are formed. In addition to that, work processes, detailed cost informations, activity time durations are taken or calculated by observing the activities. In this research, activities for overhead expenses are calculated by using TDABC method and idle capacity is determined in a logistics cargo business. The difference between theoretical and actual capacity of activities are measured by theory of constraints method and it is determined that there is a constraint in the transfer activity. By eliminating the constraint in the transfer activity, not only efficiency has been achieved but also new theoretical capacities which, are put forward with the help of a table, are calculated.