Billing and insurance-related functions have been reported to consume 14 percent of medical group revenue, but little is known about the costs associated with performing specific activities. The authors conducted semistructured interviews, observed work flows, analyzed department budgets, and surveyed clinicians to evaluate these activities at a large multispecialty medical group. They identified 0.67 nonclinical full-time-equivalent (FTE) staff working on billing and insurance functions per FTE physician. In addition, clinicians spent more than 35 minutes per day performing these tasks. The cost to medical groups, including clinicians’ time, was at least $85,276 per FTE physician (10% of revenue).