The design of business processes involves the usage of modeling languages, tools and methodologies. In this paper we highlight and address a relevant limitation of the Business Process Modeling Notation (BPMN): its weak data representation capabilities. In particular, we extend it with data-specific constructs derived from existing data modeling notations and adapted to blend gracefully into BPMN diagrams. The extension has been developed taking existing modeling languages and requirement analyses into account: we characterize our notation using the Workfl ow Data Patterns and provide mappings to the main XML-based business process languages.