The on-going quest for productivity and profitability in the current global competitive environment has created a real need for performance measurement systems that can provide relevant measures of effectiveness. Overall Equipment Effectiveness (OEE) is a Lean Manufacturing measure, used by companies trying to eliminate losses and increase their yields. Although OEE is not a new concept, existing definitions typically apply to discrete processes, making its implementation in extrusion processes challenging. Furthermore, selecting different time periods for the calculation changes the significance of the final measures. In this case study, we apply the OEE concept to an actual blown-film co-extrusion process and evaluate the effect of two different types of co-extrusion dies on the OEE and its three components; quality, availability, and performance. We also identify the operational and financial implications of OEE under the two different systems.