We conducted case studies of fourteen solo or small-group primary care practices using electronic health record (EHR) software from two vendors. Initial EHR costs averaged $44,000 per full-time-equivalent (FTE) provider, and ongoing costs averaged $8,500 per provider per year. The average practice paid for its EHR costs in 2.5 years and profited handsomely after that; however, some practices could not cover costs quickly, most providers spent more time at work initially, and some practices experienced substantial financial risks. Policies should be designed to provide incentives and support services to help practices improve the quality of their care by using EHRs.