Nearly 40 years after the adoption of the Title IX Amendments of the US Civil Rights Act, women account for almost 50% of US medical students and more than one-third of all physicians. Historically, female physicians have earned considerably less than male physicians, though in the 1990s much of this was attributable to gender differences in specialty choice and hours worked. However, more recent data suggest that female physicians currently earn less than male physicians even after adjustment for specialty, practice type, and hours worked. Salary differences between men and women currently exist among physician researchers as well. This raises questions about whether the gender gap in earnings among US physicians has closed over time, particularly compared with the earnings gap for other health care professionals and workers overall. Comparing earnings of male and female physicians over time is important in assessing the impact of policies to promote gender equality among physicians.