This brief uses data from the 2012–13 Medicare Current Beneficiary Survey (MCBS) to describe rural and urban differences in the populations that enroll in the Medicare Advantage (MA) program. Combined with county-level data on MA issuer participation, this dataset also allows us to assess the degree to which issuers may engage in selective MA market entry on the basis of observed demographic characteristics. Rural and urban MA and fee-for-service populations did not differ much by any characteristics reported in the data, including age, self-reported health status, cancer diagnosis, smoking status, Medicaid status, or by other variables assessing frailty and presence of chronic conditions. Most measures of access were similar across rural and urban respondents. While rurality on its own was often a significant predictor of lower issuer participation in a county's MA market, the addition of other demographic characteristics did not influence the prediction. In other words, we found no evidence, based upon MCBS data, that issuers exclude rural counties due to other demographics. These findings suggest that poor health – as approximated by the demographic characteristics captured in MCBS data – is also captured similarly in risk adjustment formulas, meaning that MA issuers are compensated for this observed risk.