In search for a practical solution to analyse a large quantity of medical information, rheumatic disease data base system (RDDS) is described. Details of data configuration, data entry and retrieval are discussed in some detail. The system incorporates a range of commonly used statistical tests and provisions for more advanced data analysis are made. Additional facilities include provisions for a variety of printed reports, back up facilities and a word processor. The ease of system operation and flexibility are emphasised. Technical support requirements are minimal even when new applications are being developed. The system is fully operational at present and can be implemented on a number of computer systems.