Antibiotic resistance poses serious challenges to health and national security, and policy changes will be required to mitigate the consequences of antibiotic resistance. Resistance can arise in disease-causing bacteria naturally, or it can be deliberately introduced to a biological weapon. In either case, life-saving drugs are rendered ineffective. Resistant bacterial infections are difficult to treat, and there are few new antibiotics in the drug development pipeline. This article describes how antibiotic resistance affects health and national security, how bacteria become antibiotic resistant, and what should be done now so antibiotics will be available to save lives in the future.