Since 1998, the growth of health care spending has accelerated to levels not seen since the 1980s. This growth has renewed pressures on physicians to practice “cost-effective” care, since physicians’ decisions account for the vast majority of all health care spending. But little is known about what physicians think about cost containment, and how they incorporate cost-effectiveness information into their practice patterns. This Issue Brief summarizes three related studies that describe primary care physicians’ attitudes toward considering costs in their clinical decisions, and the effects of providing cost-effectiveness information on physicians’ recommendations.