Millennials, defined as those born between 1981 and 1996, are America’s largest generation. Youth populations are surging worldwide, especially in developing countries, and these young adults are redefining wellness and doing health care their own way. Efficient technology is assumed–they want to research their medical options and manage appointments online and they favor telemedicine and wearable tracking devices. Often lacking a primary care doctor, and sometimes health insurance, millennials insist on knowing what services will cost and may be willing to forego them if the price is too steep. They demand convenience and consider wellness practices at least as useful as mainstream medicine. Health care systems will have to shake up core clinical and business practices to respond.