The focus of this study is to examine the relationship between project risk mitigation and project execution in the Nigeria oil and gas industry. Specifically, the study examines the extent of contribution of project risk mitigation in realising project budget, quality, schedule and scope during execution. In pursuant of these objectives, survey research design was used. 102 questionnaires were administered to the Managing Directors or Chief Operating Officers and project or operations managers of the selected companies. Eighty two questionnaires were validly retrieved and used for data analysis. Data obtained were analysed mean and Spearman’s rank order correlation analysis. The study found that projects risk mitigation was significantly and positively related to project execution in terms of budget, quality, schedule and scope. The study therefore recommends that there should be a holistic integration and constant improvement of project risk mitigation strategies which will help improve the quality of projects executed in the Nigerian oil and gas industry.