The rapidity with which new types of antibiotic resistance can disseminate globally following their initial emergence or recognition is exemplified by the novel carbapenemase New Delhi metallo-β-lactamase (NDM). The first documented case of infection caused by bacteria producing NDM occurred in 2008, although retrospective analyses of stored cultures have identified the gene encoding this enzyme (blaNDM) in Enterobacteriaceae isolated in 2006. Since its first description, NDM carbapenemase has been reported from 40 countries worldwide, encompassing all continents except South America and Antarctica. The spread of NDM has a complex epidemiology involving the spread of a variety of species of NDM-positive bacteria and the inter-strain, inter-species and inter-genus transmission of diverse plasmids containing blaNDM, with the latter mechanism having played a more prominent role to date. The spread of NDM illustrates that antibiotic resistance is a public health problem that transcends national borders and will require international cooperation between health authorities if it is to be controlled.