This report examines the economic and development consequences of antimicrobial resistance(AMR)-the capacity that disease-causing microorganisms acquire to resist the drugs we've createdto fight them. The report uses World Bank Group economic simulation tools to put a price tag onAMR's destructive impacts on the global economy from 2017 through 2050, if adequate measuresaren't taken to contain the AMR threat. The report highlights actions low- and middle-income countries and their development partners can take to counter AMR, and estimates the investment required. It shows that putting resources into AMR containment now is one of the highest-yield investments countries can make. Antimicrobials are drugs that destroy disease-causing microbes, also called pathogens, such as certain bacteria, viruses, parasites, and fungi. The most familiar and important antimicrobials are antibiotics, which treat bacterial infections. Other antimicrobials combat viral and parasitic diseases, such as AIDS and malaria. Since their use began some 70 years ago, antimicrobials have saved hundreds of millions of lives.