In this paper we present a hybrid approach to Life Cycle Assessment (LCA) using the case study of an electronically controlled unit injector (EUI), which is a time-controlled fuel injection system. Using the hybrid approach, we are able to quantify environmental information on upstream production processes preceding manufacture at Bosch without the need to gather all supplier data empirically. Life Cycle Inventory (LCI) data based on “conventional” process models are combined with LCI data from economic input-output relations between different industry sectors and associated pollution discharges and nonrenewable resource consumption. The economic input-output-based LCA (EIO-LCA) allows us to quantify indirect environmental impacts of production processes generally neglected in conventional LCA models. As EIO-LCA quantifies environmental impacts on a rather aggregate level, additional process models for LCA are used to account for specific characteristics of the processes investigated. The hybrid approach significantly reduces the effort required for data gathering and analysis and allows for a more comprehensive assessment of the environmental burdens associated with a product or process. To validate our approach, we contrast the results of the hybrid LCA to the results obtained from a conventional process LCA.