According to SK&A Healthcare Information Solutions’ (SK&A) Physician Office Acceptance of Government Insurance Programs Report, 83 percent of physicians’ offices accept Medicare and 65 percent accept Medicaid.  In addition, this report found that Medicare and Medicaid acceptance varied by size, ownership, location, and specialty of physicians’ practices.  Larger practices are more likely to accept Medicare patients than smaller practices, while hospital-owned practices are more likely to accept Medicaid than non-hospital-owned practices.

From the press release:

For example, large practices with 26 or more physicians are more likely to accept Medicare (87.1%) and Medicaid (83.6%) than smaller practices with between one and 10 physicians. The higher the patient volume, the more likely it is the practices accept these programs. Offices with daily patient volumes greater than 31 have acceptance rates of 84% for Medicare and 68.4% for Medicaid.

Press release: http://www.pr.com/press-release/188966

SK&A Healthcare Information Solutions (2009). Physician office acceptance of government insurance programs.