The humanitarian emergency in Venezuela, and resulting collapse of its primary health care infrastructure, has caused measles and diphtheria to reemerge — disproportionately affecting indigenous populations — and spread to neighboring countries. This sets the stage for the potential reemergence of polio. The re-establishment of measles as an endemic disease in Venezuela (with >5,500 confirmed cases) and its spread to neighboring countries threaten the measles-free status.