This book constitutes the proceedings of two events held at the CAiSE conference and relating to the areas of enterprise, business process and information systems modeling: The 19th International Conference on Business Process Modeling, Development and Support, BPMDS 2018, and the 23rd International Conference on Evaluation and Modeling Methods for Systems Analysis and Development, EMMSAD 2018. The conferences took place in Tallinn, Estonia, in June 2018. The 13 papers accepted for BPMDS were carefully reviewed and selected from 29 submissions; for EMMSAD 6 papers out of 13 submissions were accepted for publication. For BPMDS 2018, the papers were organized in topical sections as follows: context-awareness in business processes; automatic analysis of business processes; advanced approaches for business process modeling; evaluation of business process modeling techniques; an experience report on modeling collaborative processes. For EMMSAD 2018, the six related papersare listed without further sections.