This paper describes the on going experience of Caliò Informatica Srl in a project of Process Improvement Experiment (PIE) sponsored by the Community's ESSI (European Systems and Software Initiative) program. The experiment concerns the improvement of two primary Software Life Cycle (SLC) processes, namely Analysis and Design, by adopting Object Oriented technology, and in particular the UML method. Rational Rose is the technology, which is supporting the improvement. The PIE is being done on top of a strategic baseline project, being deployed by Caliò Informatica, in the business domain of enterprise management applications.