From 2025, the KRITIS Act will regulate the resilience and physical security of critical infrastructures. In conjunction with the EU Directive on measures for a common level of cybersecurity across the European Union (NIS 2 Directive) and supplemented by industry-specific security standards (e.g. from the German Technical and Scientific Association for Gas and Water), the requirements for the monitoring of critical facilities are now increasing for operators. Digital twins offer excellent features for integrating them into critical infrastructure assessment procedures. As a mirror image of real hardware components (e.g. building information from BIM, characteristic data of machines) and environmental events (water levels, weather phenomena, etc.), the sensor data of the digital twins transfer their measured values and observations into manual, partially or fully automated inspection processes. The presentation describes this integration of information technology and operational technology (IT/OT convergence) to be implemented with the help of digital twins and refers to the corresponding catalogues of measures of the BSI (Federal Office for Information Security) for KRITIS assessments.