Ever increasing attention is being paid to the challenge that society faces with the continuing development of antibiotic resistance. Many years of excessive and inappropriate use of antibiotics has accelerated the development of resistance. It is a problem concerning several societal sectors and services, and as a consequence must be dealt with at all levels: locally, nationally and internationally. In accordance with the Swedish Civil Contingencies Agency’s (MSB) mandate to analyse particularly serious vulnerabilities, threats and risks, the MSB has in this study investigated what an extensive antibiotic resistance could entail for societal security. Increasing antibiotic resistance threatens not only lives and health but might also affect vital societal functions. Examples include the medical services, pharmaceutical supplies, care facilities, food, drinking water supply, sanitation and the fire and rescue ser vices. Public trust and confidence in societal institutions might diminish and the societal costs of antibiotic resistance could be extensive. A more extensive antibiotic resistance could also complicate the management of certain types of emergencies. Unless the development of antibiotic resistance can be slowed down, medical care in the future could encounter major problems regarding treatment of injuries caused by big accidents and crises, or with the bacterial secondary diseases (sequelae) that follow a pandemic.