Activity based funding is an essential part of hospital management. Diagnosis Related Groups (DRGs) is the best-known classification system that is used in this funding model. Such model was adapted in France within the PMSI (Programme de Médicalisation des Systèmes d’information) that takes into account diseases, procedures and treatments. Coding of patient stays should be consistent with the actual care provided. We assume that cross-checks between the electronic health record (EHR) and information coded in the PMSI can improve both PMSI and the EHR. Quality control of PMSI data and quality of care are first carried out by physicians and technicians of coding units, and then verified by physicians from the social insurance in relation to the coding units, and the French High Authority for Health (HAS) through the certification process. These checks involve a fair semantic interoperability between different medical applications, from EHR to PMSI system and vice versa. The objective of the TOLBIAC project (Terminologies and Ontologies for Linking Billing Information and Accurate Clinical data) is to define, model, implement, and evaluate the automated bi-directional consistency between information from the EHR and those coded in the PMSI. In order to achieve this objective it is necessary to: 1) Formalize the rules for analyzing the relationship between the EHR including clinical data from the Health information system on the one hand, and the PMSI on the other hand. 2) Set rules that allow to check the consistency. 3) Implement this methodology in hospital information systems, EHR and PMSI medical applications to: a) ensure the relevance and accuracy of coding by comparing data from multiple sources of information (biological, clinical, administrative, ...); b) assess the financial impact and efficiency of consolidated features. The TOLBIAC consortium consists of 4 public partners (University hospital of Saint-Etienne, University hospital of Nice, CISMeF team from University hospital of Rouen and Hospital of Firminy-INSERM U707) and three private partners (VIDAL, Web100T and InterSystems). The business plan and the consortium agreement will be defined with the help of seven partners. The project lasts 36 months and is divided into seven tasks (T0: coordination and project management; T1: requirements analysis, use cases, T2: formalization of regulatory constraints of the PMSI; T3: modeling methods: representation of management rules for quality and consistency of data using statistical methods and probabilistic approaches, and semantic and linguistic analysis; T4: integration, implementation, prototyping, T5: validation of tools and impact assessment; T6: dissemination and exploitation of the results ). Solutions related to the use cases will be implemented in three pilot sites (1) University hospital of Saint-Etienne in partnership with Web100T using the CristalNet EHR data, (2) University hospital of Nice with a comparison between the medico-economic data entered in the Clinicom software provided by InterSystems and data from the Agfa HealthCare EHR, and (3) Hospital of Firminy – INSERM U707. The result of the project includes production of a set of PMSI-EHR matching rules implemented and validated in pilot sites. The purpose is to ultimately provide a tool capable of producing from clinical data described in the EHR, a transcription of the patient stay as exhaustive as possible in the PMSI using data from all information sources available.