Recently, two largest-scale branches of software development, where CASE tools are efficiently used - information systems and real-time control systems - are observed to close in. In large information systems, a software response rate problem arises when servicing a big number of clients. As a rule, real-time control systems not only control specific equipment, but also work with a database. In this paper, the RTST++ object-oriented methodology is presented, which is created on the basis of UML, SDL, and ROOM, with certain elements of the structured approach (basically, for the convenience of relational database development) and reflects the tendencies mentioned above. Along with this, a CASE tool implementing this methodology, RTST++, is presented.