Abstract: Regulations in Indonesia requires foreign companies to have local partner in a joint operation if they want to enter Indonesia contruction industries. This study will examine company ”X”, who frequently get join operation project offers from foreign companies. Within that joint operation, beside many advantages, there are also some risks to manage. Risks in a joint operation project will be more complex than projects in general, because it involve two or more companies with different culture. The purpose of this study is to indentify important risk factors in joint operations project by company ”X”. The instruments of this study consist of primary data (interview and questionaire) and secondary data (books and journals of relevant studies). The datas gathered then analyzed using risk analysis method with Risk Significance and Relative Importance Index as to obtain the risk variables with significant influence on these three porjects in this study. Based on the study, it is found that the important risk variables in a joint operation projects with foreign companies by company ”X” are distrust between employees of each company (X9) and language limitations (X30). Therefore, it is recommended to set a minimum standard of language skills (especially English) for the staff who will assigned in the joint operation project with foreign company also to provide language skills training and it is recommended that the directors from each parent’s company could ensure staff commitment, coordination, and trust by enhancing communication quality and a conflict resolution technique. Carefully selecting a staff for joint operation proyek and employing unbiased and experienced staff are effective measures to remove the distrust within the staff