Women are more likely to receive mammography if they see a female, rather than a male, physician (Lurie et al., 1993). This difference in mammography use could arise from differences in the behavior of male and female physicians, or from differences in their patients. This paper examines the extent to which differences in mammography use are attributable to physician differences, controlling for patient differences, and expands on previous research by examining both demographic and attitudinal differences between the patients of male and female physicians. A population based sample of Washington State women (n = 852) between the ages of 50 and 80 years old were asked to complete an extensive telephone interview regarding their demographic and attitudinal characteristics, their mammography use, and the gender of their primary care physician. Women patients of male and female physicians were not found to differ significantly in their education, financial status, employment, assertiveness with their physician, or values regarding physician characteristics including preventive care and communication skills. Analyses conducted to examine the contribution of physician gender to mammography use revealed almost a two-fold reduction in screening associated with having a male physician (adjusted odds ratio 1.95; p < .05). Differences in mammography use associated with male and female physicians do not appear to arise from characteristic demographic or attitudinal differences between their patient populations.