High global competition forces manufacturers to continuously aim for optimizing their processes. Identifying and eliminating waste and streamlining the value chain, are the main objective of lean. Therefore, many companies use this tool to provide an optimized value chain. However, it is often seen that the interfaces in between the process steps are forgotten. Based on empirical data from five different organizations from different industries, the following question will be addressed: In what way does lean contribute to achieve value chain integration?