Formal Safety Assessment is a very important tool for the establishment of safety systems according to marine safety. FSA methodology has been recommended to all the maritime actors by the International Maritime Organization (IMO) as an integrated safety system. In Formal Safety Assessment two main risk methodologies are applied, which are quantitative and qualitative risk assessments. Both of these methods are used together in practice. The FSA approach is applied in five main stages. In this study, risks related to marine traffic in the Istanbul Strait in the period of 2001-2010 are analyzed. In practice, different factors are selected for risk analyses such as vessel specifications, accident locations, accident time, accident types and causes. (C) 2015 The Authors. Published by Elsevier Ltd.