This article describes the chances microstructured reactors offer for chemical plant engineering. This suitability for chemical production is commonly regarded to be the key to the market penetration. Seen in the long term, there is potential that new plants can be equipped with microstructured reactors. Only economic balances, however, which draw up profitability, will open the door to the usage of chemical micro process engineering for plant construction. Main arguments for using microstructured reactors are thus enhanced conversion and selectivity, increased space-time yields, waste reduction and more safety via small reactor volumes. Credit-card sized reaction systems allow one to perform the screening of multi-phase reactions. More prominent, similar screening is carried out for single-step reactions. Moreover, safe processing with microstructured reactors in the explosive regime enlarges the traditional range of processing. The reaction guidance by microstructured reactors can further influence subsequent processing steps such as product purification and, in this way, can lower the energy costs of processes.