In this paper, we present a platform independent model (PIM) of IIS*Case tool for information system (IS) design. IIS*Case is a model driven software tool that provides generation of executable application prototypes. The concepts are described by Meta Object Facility (MOF) specification, one of the commonly used approaches for describing meta-models. One of the main reasons for having IIS*Case PIM concepts specified through the meta-model, is to provide software documentation in a formal way, as well as a domain analysis purposed at creation a domain specific language to support IS design. Using the PIM meta-model, we can generate test cases that may assist in software tool verification. The meta-model may be also a good base for the process of the concrete syntax generation for some domain specific language.