BACKGROUND: There is considerable interest in measuring and eliminating health care disparities among various special populations, but there is limited understanding of their extent, causes, or potential remedies. To improve this for tobacco cessation, we measured differences in the frequency of receiving and filling cessation medication prescriptions by race, ethnicity, age, language preference, health insurance, and pregnancy. METHODS: The relevant variables for all patients of a Minnesota medical group aged 18 years and older with clinician visits were extracted from the electronic medical records of 1 large medical group from March 2006 to February 2007. This was combined with claims data from 1 insurance plan that covered most of these individuals. Order and fill rates for cessation medications were then adjusted for each of the other variables. RESULTS: There were 32,733 current users of tobacco, 18,047 of whom had both health insurance and pharmacy claims data available. After adjustment, 15.4% overall had received an order for cessation medications during this year, but only 78% had filled it. Groups receiving fewer orders than their comparison groups were aged 18-34 years or older than 65 years, men, pregnant women, Asians and Hispanics, and those with non-English-language preference, on Medicaid, or with fewer visits. The same groups were less likely to fill that prescription, except patients with non-English preference or Medicaid. DISCUSSION: There are disparities in both the receipt of cessation medication orders and the likelihood of filling them for some special populations. The causes are likely to be complex, but this information provides a starting point for learning to improve this problem.