The main objective of this study was to identify factors influencing the effectiveness of application of the integrated approach to risk analysis and mitigation, the so-called GRC (Governance, Risk management, Compliance) and to assess the degree of preparation of Polish construction companies to implement this approach. In the research, an idiographic approach, a case study procedure, were used. The analysis was carried out on the two largest Polish capital groups in the construction sector, Budimex and UNIBEP. The carried out case studies made it possible to describe the practices applied by construction companies which are important for the effectiveness of the GRC. These practices were shown in five groups of factors, such as: corporate policies and procedures/supervision, communication and training, ethical organisational culture, responding to and preventing future incidents, risk management. The research shows that although Budimex and UNIBEP's approaches to the GRC differ in several respects (Budimex shows greater diligence in fraud prevention), in general the degree of preparedness of both groups to implement the GRC can be considered as satisfactory.