The recently enacted stimulus bill–the American Recovery and Reinvestment Act of 2009 (ARRA)–touches almost every aspect of the U.S. economy. Health care is no exception. In fact, the ARRA is historic health care legislation of the type rarely produced by our famously incremental federal government. The law prevents dramatic state cuts in Medicaid, expands funding for preventive health care services and health care research, and helps the unemployed buy health insurance. But perhaps its most profound effect on doctors and patients will result from its unprecedented $19 billion program to promote the adoption and use of health information technology (HIT) and especially electronic health records (EHRs). The HIT components of the stimulus package–collectively labeled HITECH in the law–reflect a shared conviction among the fledgling Obama administration, the Congress, and many health care experts that electronic information systems are essential to improving the health and health care of Americans. However, proponents of HIT expansion face substantial problems. Few U.S. doctors or hospitals–perhaps 17% and 10%, respectively–have even basic EHRs, and there are significant barriers to their adoption and use: their substantial cost, the perceived lack of financial return from investing in them, the technical and logistic challenges involved in installing, maintaining, and updating them, and consumers’ and physicians’ concerns about the privacy and security of electronic health information. HITECH addresses these obstacles head on, but huge challenges await efforts to implement the law and fulfill President Barack Obama’s promise that every American will have the benefit of an EHR by 2014.