Companies deploy workflow management systems which interpret process models to ensure compliance of operational duties by automatically distribute work items to employees or machinery. Enterprises are often forced to outsource services and join interorganizational collaborations, e.g. in supply chain scenarios, to remain competitive on the market. Today, interorganizational process management cater for interconnecting publicly visible tasks of the participants’ local workflows whereby a predefined message exchange protocol ensures interoperability. Especially in flexible large-scale collaboration scenarios, this strategy lacks in global monitoring or transparent data-based routing the control flow due to a missing central controlling instance or global accessible data. Blockchain technology promises to automatically run applications in a decentralized fashion without any trusted third party needed, as participants will agree on a common valid state algorithmically. We capitalize on this consensus finding mechanism and tamper-resistant data storage to propose a novel form of workflow interoperability for interorganizational workflows which autonomously orchestrates the process in-between. The approach solves issues regarding the monitoring of the global state, the distribution of work items to the respective business partners and achieves data-based routing by holding in-process variables decentralized in a trustworthy fashion.