Marine fish farming is one of Norway’s largest industries and exports. The industry is in rapid development and secures employment for several thousand people, all along the Norwegian coastline. Fish farming is regarded as a relative sustainable method for food production. However, the industry is still prone to certain challenges and problems. Escape of fish, for instance, is one of the industry’s main challenges and also the emphasis of this thesis. Interactions between escapees and wild populations are unwanted because of potential for interbreeding, competition for food and transfer of disease and pathogens. Financial penalties and damaged reputations are additional downsides related to the escape of fish. This thesis investigates the risk of fish escape from marine fish farms. The Directorate of Fisheries’ database on previous escapes is reviewed and literature studies are performed to reveal particular causes and factors associated with the escape of fish. Furthermore, the concept of risk indicators is utilized in order to provide a means for monitoring the risk of escape. The underlying principle is that by measuring the state of risk-influencing factors (RIFs), it is possible to monitor how the relative risk level develops. However, RIFs are not necessarily directly measurable, thus indicators are developed as tools for measuring the state of RIFs. Consequently, risk-mitigating measures can be implemented at the correct time and the correct place in order to prevent or reduce the probability of escapes. It is believed that the database on previous escapes may be utilized to a greater extent in preventing future escapes. This may be achieved by, for instance, making the database available to the public and by considering the possibility of including underlying and organizational aspects with potential influence on escapes. However, through assessment of the current method for data collection on fish escapes, it is revealed that the database is prone to certain limitations and challenges. To cope with these challenges, the thesis suggests potential measures in order to improve the validity and general usefulness of the database. To the author’s best knowledge, no previous work exists on the use of risk indicators within marine fish farming. Thus, this thesis relies upon similar works within oil and gas (O&G) to assess the problem. The O&G industry utilizes technical safety barriers to prevent major accidents, e.g. hydrocarbon leaks. These barriers are then candidates for indicator development. However, the only evident technical safety barriers to prevent escapes are the main components of the fish farm itself. This creates a challenge in identifying suitable technical risk indicators. However, organizational and human aspects are more comparable between the industries. In this regard, this thesis proposes a set of indicators and RIFs to monitor the risk of escape from marine fish farms. They are, however, presented without any form of testing, and would benefit from further assessment using field data and expert judgments.