The paper presents the solution adopted to index the information in a Multimedia Database Management System dedicated to medical domain, being optimized for medium sized databases. The system automatically processes the images inserted into database, extracting characteristics as: color histogram, texture, and color regions. The system contains the needed algorithms for images processing and visual content-based retrieval, thus making the client applications less complex. The information is indexed using a single level B-tree structure for text-based data, and using an R-trees structure for multimedia data. The performances of the system are analyzed from the execution time point of view.