The Unified Modeling Language (UML) is a general purpose visual modeling language that is designed to specify, visualize, construct and document the artifacts of software systems. UML sequence diagrams describe a collaboration of interacting objects, where the interactions are exchanges among communicating entities in real time and distributed systems. Like any other aspect of the specification and design process, the specifications in UML sequence diagrams are susceptible to errors, and their analysis is necessary.A tool for timing analysis of UML sequence diagrams is described in this paper.