There is a widespread belief by some health care providers and the wider community that medications used to alleviate symptoms may hasten death in hospice patients. Conversely, there is a clinical impression among hospice providers that hospice might extend some patients' lives. We studied the difference of survival periods of terminally ill patients between those using hospices and not using hospices. We performed retrospective statistical analysis on selected cohorts from large paid claim databases of Medicare beneficiaries for five types of cancer and congestive heart failure (CHF) patients. We analyzed the survival of 4493 patients from a sample of 5% of the entire Medicare beneficiary population for 1998-2002 associated with six narrowly defined indicative markers. For the six patient populations combined, the mean survival was 29 days longer for hospice patients than for nonhospice patients. The mean survival period was also significantly longer for the hospice patients with CHF, lung cancer, pancreatic cancer, and marginally significant for colon cancer (P=0.08). Mean survival was not significantly different (statistically) for hospice vs. nonhospice patients with breast or prostate cancer. Across groups studied, hospice enrollment is not significantly associated with shorter survival, but for certain terminally ill patients, hospice is associated with longer survival times. The claims-based method used death within three years as a surrogate for a clinical judgment to recommend hospice, which means our findings apply to cases where a clinician is very sure the patient will die within three years, and it points to the need to validate these findings.