The Unified Modeling Language is the new official OMG standard for object-oriented modeling languages. This volume contains papers presented during the 1st GROOM-workshop on the Unified Modeling Language (UML). GROOM (Grundlagen objektorientierter Modellierung) is a working group of the Gesellschaft fur Informatik (GI), the German Society of Computer Science. The papers are presented in three chapters as follows: UML vs. other approaches - business process modeling and applications - technical aspects and concepts. Researchers and practitioners interested in object-oriented software...