Since 1982 Bell Canada has been developing a model to assess the software development process of existing and prospective suppliers as a means to minimize the risks involved and ensure both the performance and timely delivery of software systems purchased. This paper presents the revised Trillium model (version 3.0). The basis of the process assessment models for software relies on benchmarking, e.g. comparing your practices with the best and successful organizations. It is also a basic tool that you will find in the TQM literature. For software assessment we have used initially two levels of benchmarks to develop the model: professional, national and international standards; and comparisons with other organizations in the same market segment. The software assessment model should therefore map to existing engineering standards as well as quality standards. It should also provide an output that can be used easily to benchmark against "best-in-class" organizations.