In the domain of production, Manufacturing Execution Systems (MES) are becoming increasingly popular. State of the art MES not only bring interfaces to a large variety of shop floor systems, they also come with functionality for data integration, data analysis, and dashboard generation – features commonly associated with Business Intelligence (BI) systems. At the same time, Data Warehouse (DHW) based BI infrastructures are increasingly extended to the support of operational managerial levels (Operational BI). This contribution sheds light on whether or not BI systems and MES are at odds and in how far they are complementary. To achieve this, two subsequent studies have been conducted: a case study based exploration and a quantitative online survey. The study results motivate an integration framework for MES and BI systems.