Current systems that target Patient Safety (PS) like mandatory reporting systems and specific vigilance reporting systems share the same information types but are not interoperable. Ten years ago, WHO embarked on an international project to standardize quality management information systems for PS. The goal is to support interoperability between different systems in a country and to expand international sharing of data on quality and safety management particularly for less developed countries. Two approaches have been used: (i) a bottom-up one starting with existing national PS reporting and international or national vigilance systems, and (ii) a top-down approach that uses the Patient Safety Categorial Structure (PS-CAST) and the Basic Formal Ontology (BFO) upper level ontology versions 1 and 2. The output is currently tested as an integrated information system for quality and PS management in four WHO member states.