Cable ageing and the need for condition monitoring are the most important aspects of plant life extension when it comes to instrumentation and control systems. Cables, especially their insulation and jacket material, are vulnerable to ageing degradation during normal operation, and means must be established to ensure that cable ageing does not lead to unsafe operation. This publication addresses all relevant issues related to cable ageing and contains introductory level materials that present a summary of key issues in cable ageing in nuclear power plants. In particular, it provides guidelines for cable qualification and cable ageing management in nuclear facilities, reflecting the technical advances of the past 15 years.