A major challenge in information management today is the integration of huge amounts of data distributed across multiple data sources. A suggested approach to this problem is ontology-based data integration where legacy data systems are integrated via a common ontology that represents a unified global view over all data sources. However, data is often not natively born using these ontologies. Instead, much data resides in legacy relational databases. Therefore, mappings that relate the legacy relational data sources to the ontology need to be constructed. Recent techniques and systems that automatically construct such mappings have been developed. The quality metrics of these systems are, however, often only based on self-designed benchmarks. This paper introduces a new publicly available benchmarking suite called RODI, which is designed to cover a wide range of mapping challenges in Relationalto- Ontology Data I ntegration scenarios. RODI provides a set of different relational data sources and ontologies (representing a wide range of mapping challenges) as well as a scoring function with which the performance of relational-to-ontology mapping construction systems may be evaluated.