www.informatik.uni-ulm.de/pm/mitarbeiter/fruehwirth/ Abstract. The challenges of the Semantic Web endeavour in knowledge representation and reasoning prompted a wealth of research in combining description logic (DL) as ontology languages (e.g. OWL) with logic programming for rule-based reasoning. General issues of combining and integrating formalisms have to be faced such as the type of combination, conceptual simplicity and tractability. Even though constraint-based programming has a tradition of tackling these questions, constraint-based rule formalisms such as constraint logic programming, concurrent constraint programming, constraint databases and constraint handling rules (CHR) have not explicitely been considered for combination with DL yet. The same holds for concurrency, which is an essential characteristic of the internet, but to the best of our knowledge has not been related to DL so far. Since CHR is a very expressive declarative concurrent constraintbased programming language with optimal performance guarantee and other interesting properties, we explore in this speculative paper what a CHR-based approach would look like in comparison to recent approaches for integrating OWL and rules.