MoBIoS is a specialized database management system whose storage manager is based on metricspace indexing, and whose query language entails biological data types. When relational database management systems are used to support biological data, important data types are relegated to blob and unstructured text fields. Thus, even simple, but critical queries are executed by sequentially dumping the data to utilities outside the database. MoBIoS provides O(log n) physical access to diverse biological data types as well as uniform logical and syntactic access. Consequently, MoBIoS provides a framework where complex bioinformatic algorithms may be effectively expressed and executed as concise declarative SQL-like queries.