: There is relatively little research on software Project Estimation and Measurement Systems (PEMS). Commercial PEMS vary in functionality and effectiveness. Their intended users thus do not know what to expect from PEMS and how to evaluate them. This paper creates an information system design product theory for the class of PEMS that prescribes the meta-requirements, the meta-design, and applicable theories for all products within the class. Meta-requirements and the meta-design are derived from the project estimation and measurement literature, experiences obtained during more than ten years of empirical work in Finnish Software Measurement Association, and a commercially available PEMS.