Abstract Clinical evaluation is a structured ongoing procedure to collect, appraise and analyse clinical data pertaining to a medical device. The clinical data include current knowledge of the condition to be treated, published literature about the target device and any equivalent devices, information held by the manufacturer about pre-clinical and clinical investigations, risk management, post-market surveillance, and the instructions for use. The clinical data are analysed for consistency between them to identify any gaps or uncertainties that require further evaluation, and to show conformity with the Essential Requirements of the Medical Devices Directive (to be superseded by the Medical Devices Regulation). The clinical evaluation report (CER) is the document containing this information to support initial CE-marking or CE renewal. The guideline determining the structure and content of the CER is MEDDEV 2.7/1 Rev. 4 ( June 2016). This article provides an overview of how to write a CER according to this guideline.