Crime prevention and safety measures in socio-economically vulnerable areas are important incentives for creating a socially sustainable city. The topic has been debated in Sweden, and to address the challenges, a new law in Sweden will come into force on June 1, 2023, giving Swedish municipalities greater responsibility for crime prevention. Previous research indicates that crime prevention and safety promotion can be categorized based on physical and social efforts. These efforts are partly about creating better social cohesion between people and partly about changing the physical environment to make it more difficult for people to commit crimes. The master thesis aimed to study crime prevention and safety promotion measures in two socio-economically vulnerable areas in Sweden to find out how the work can be developed through the theories of social sustainability, social disorganization theory, and collective efficacy. The results indicate that both neighborhoods work with social and physical measures, but that their circumstances are different. This is because crime statistics indicate that Gottsunda has significantly more crime rates than Klockaretorpet. Finally, the results show that it is important to implement both social and physical measures in socio-economically vulnerable areas. The study was conducted through qualitative interviews with planners, police, property owners, and one social sustainability consultant. A document analysis of policy documents has also been conducted. Furthermore, crime statistics from the police have been analyzed to visualize the number of reported crimes in the neighborhoods