Megaprojects are temporary endeavors that involve high investments and long term results, high degree of uncertainty and risks. The purpose of this article is to stablish a critical comparative analysis of the quantitative risk analysis process in megaproject schedules. The methodology includes a study of the scientific literature and the empirical evidence obtained from interviews with specialists of an oil and gas segment company. A systematic survey of the scientific literature was carried out in ISI Web of Science, Scopus and Scielo databases. The primary data collection was carried out through interviews with a sample of 10 professionals with high level of seniority. As results, the evidences indicate that there is restricted scientific literature on the subject in peer reviewed journals, which suggests an academic contribution of the present study. In addition, Monte Carlo simulation is the most frequent technique used in risk management of megaproject scheduling that provides precision to the probability of project completion data. Besides, it was observed an existence of subjectivities, such as the bias of experts, not judgment of the time estimates of activities, and gaps, such as an inconsistency of the logic of the schedules, no process of quantitative risk analysis. Finally, it was detected the need for training in risk management of hierarchical senior managers, as a way to contribute to the achievement of better results with the use of non-decision-making practice.