The importance of integrated modelling of urban wastewater systems is ever increasing, also due to the European Water Framework Directive. In order to facilitate its practical application, the Central European Simulation Research Group (HSG) has prepared a guideline document, suggesting a seven-step procedure to integrated modelling. Findings of recent research and application projects in Central Europe have been integrated in the guideline. The present paper outlines this guideline document. The full guideline will be made available on the Internet.