As databases in the human genome project proliferate, it is important for users of one genomic database to identify similar or inconsistent data in other autonomously developed genomic databases. To do so, the user needs to issue the same query across multiple databases. We describe an approach that allows a query issued against one database to be automatically mapped to an equivalent query against another structurally different database. Our approach features two components: 1) a database designed to capture knowledge (metadata) that describes the correspondences among individual database components and 2) a module that utilizes the metadata to perform query mappings. As a demonstration, we apply our query mapping approach to two chromosome map databases (DB/12 and GDB).