A method and apparatus to automatically map between disparate message formats are provided. In one embodiment, the mapping begins by message selecting a target field in a target business object. A concept associated with the target field is identified in a synonym dictionary. A set of synonyms associated with the concept is received. In the source document, fields are identified which contain synonyms that match the synonyms in the target field. For those source fields that match the target field, a match exists and the fields are said to be mapped.