We describe a performance modeling framework that can be used in the development and maintenance of component-based distributed systems, such as those based on the CORBA, EJB, and COM+ platforms. The purpose of the framework is to produce predictive performance models that can be used for obtaining performance related information on the target system at all stages of its life cycle. The framework defines a UML-based notation for describing performance models, and a set of special techniques for modeling component-based distributed systems. In addition, we present a transformation for converting the resulting models into a format that can be solved approximately for a number of relevant performance metrics.