AVL’s customers (OEMs) face the challenge of keeping down their products’ ex works prices while offering product features that lead to the lowest possible life cycle costs. At the same time, legislative authorities continuously define stricter requirements regarding fuel consumption and exhaust emissions. To meet these requirements, technological innovations in powertrain systems need to be found, the consequences of which typically result in increased development and production costs. If this increase in costs results in higher purchase prices for the end customer, then these additional expenses need to be compensated for and justified with lower operating costs and TCO. In many cases, the development of more sophisticated systems results in increased effort for the adaptation of infrastructure facilities and activities concerning the application, installation and maintenance as well as increased disposal and processing costs for environmentally harmful components. The scope of this master thesis is the development of a methodology that identifies the Total Cost of Ownership of powertrain systems while representing the mentioned dependencies. In a second step, the developed process is implemented in an Excel based TCO calculation tool that considers further influences such as fluctuating prices, interest and inflation rates in different markets. Finally, the tool is tested with particular applications and recommended actions are derived. The focus on commercial powertrain applications results in Brake Specific Fuel Consumption (BSFC) being identified as the most dominant cost driver over the powertrain’s life cycle. Commercial applications in this thesis are represented by engines with a range of performance between 300 kW and 4000 kW. Such power ratings are necessary for the commercial vehicle sector as well as the large engine industry with applications in mining and construction, oil and gas, marine, locomotive and power generation. The integration of the TCO methodology and calculation tool into existing processes and development activities is a major aim of the present thesis as it provides the basis for the engineers’ acceptance and utilization of the tool.