The goal of the EUCLIDES project was to provide a European standard for clinical laboratory data exchange between independent and heterogeneous Medical Information Systems. EUCLIDES aims an open standard i.e. freely avialble to all, and unbiased towards any manufacturer's hardware or software. By convergence with other emerging standards, it could develop into a world standard. It could also be extended to other fields of medicine. EUCLIDES addresses the data exchange problem in a three-pronged approach : 1. the message transfer-mechanism, 2. the message syntax, and 3. the medical coding systems used within the message. Moreover, the EUCLIDES system offers through the EUCLIDES BRIDGE a user-friendly software solution for interfacing with existing local systems at both the sender's and receiver's ends.