Abstract: “The construction phase of the project implementation stage where the contractor has won the tender and has been prepared for the construction process, is an activity that contains the uncertain events which interact and may originate from internal and external environment of the project. Contractor as responsible and resource managers, must take into account the uncertain events that may lead to the risk of increased costs of the project compared to the initial cost estimate as a consequence of the unforeseen costs that arise during the course of construction. This study aims to identify uncertain events during the execution of the project, then the distribution of the uncertain events to appropriate parties to obtain the uncertain events that are the responsibility of the contractor. Primary data were obtained from several contractors in Indonesia through interviews and questionnaires, while secondary data obtained from the documentation for the implementation of the project. The resu”

Keywords: uncertain events, risk, project construction, information, upcoming projects