Abstract Background The definition, classification and management of rectus diastasis (RD) are controversial in the literature and a variety of different surgical treatments have been described. This article reports on the European Hernia Society (EHS) Clinical Practice Guideline for RD. Method The Guideline group consisted of eight surgeons. The Grading of Recommendation, Assessment, Development and Evaluation (GRADE) approach and the Appraisal of Guidelines for Research and Evaluation (AGREE) instrument were used. A systematic literature search was done in November 2018 and updated in November 2019 and October 2020. Nine Key Questions (KQs) were formulated. Results Literature reporting on the definition, classification, symptoms, outcomes and treatments was limited in quality, leading to weak recommendations for the majority of the KQs. The main recommendation is to define RD as a separation between rectus muscles wider than 2 cm. A new classification system is suggested based on the width of muscle separation, postpregnancy status and whether or not there is a concomitant hernia. Impaired body image and core instability appear to be the most relevant symptoms. Physiotherapy may be considered before surgical management. It is suggested to use linea alba plication in patients without concomitant hernia and a mesh-based repair of RD with concomitant midline hernias. Conclusion RD should be defined as a separation of rectus muscles wider than 2 cm and a new classification system is suggested.