Patient safety is one of the most significant issues not only to medical providers but also to the general public. Despite the widespread recognition of the adverse event reporting for patient’s safety, there is no widely accepted or standardized way to request and report adverse event information. We designed the semantically interoperable Adverse Event Reporting framework. It consists of two components: the Adverse Event Ontology to describe adverse event in semantically interoperable way and the Adverse Event Reporting Schema (AERS) to envelope and deliver the content of adverse event report request and report. The Adverse Event Ontology was built upon existing adverse event taxonomies. The AERS was designed for common adverse event messaging interface in the form of XML Schema. The adverse event reporting framework is expected to allow semantic interoperability in sharing and exchange of patient safety information within and among various healthcare information systems.