This report is intended to support hospitals in developing procedures for the commissioning and quality assurance (QA) of computerized treatment planning systems (TPSs). The relatively low cost of today's equipment has made TPSs widely available in industrialized and developing countries, but, with the exception of a few national recommendations for QA in North America and Western Europe, there are no publications available that professionals can follow to develop procedures to check their TPSs. The rationale for the multiple tests described in this report is related to the four major issues of a well structured QA programme in computerized treatment planning, namely education, verification, documentation and communication.