Background: Many persons dying of cancer enroll in home-based hospice prior to death. It is established in the literature that persons in rural settings are less likely to use hospice than persons living in urban areas. We examine whether this is due, in part, to a lack of hospice providers serving rural areas. Methods: The 100% Medicare enrollment and hospice files for 2000-2002 were the basis for this study. We used a Bayesian smoothing technique to estimate the ZIP-code-level service area for each Medicare-certified hospice in the United States. These service areas were combined to identify ZIP codes not served by any hospice. Results: Overall, approximately 332,000 elders (7.5% of ZIP codes) reside in areas not served by home-based hospice. Each year over 15,000 deaths occur in these unserved areas. There was a strong association between lack of service and urban/rural gradient. One hundred percent of the ZIP codes in the most urban areas (>1,000,000 people) are served by hospice and only 2.8% of the ZIP codes in urban areas of less than 1,000,000 are unserved. In rural areas adjacent to urban areas, over 9% of ZIP codes are unserved and in rural areas not adjacent to an urban area almost 24% of ZIP codes are not served by hospice. Conclusions: While the majority of the elderly population of the US resides in areas currently served by Medicare-certified hospice, there is a geographically large area that lacks home-based hospice services. Current payment policies may need to be adjusted to facilitate hospice availability to these rural populations.