Palliative care consultation is the most common model of hospital-based services in the United States, but few studies examine the impact of this model. In a prospective study, we describe the impact of palliative care consultation on symptoms, treatment, and hospital costs. Patients receiving interdisciplinary palliative care consultations from 2002 to 2004 were approached for enrollment; 304 of 395 (77%) patients participated. Measures included diagnosis, treatment decisions, and symptom scores. To test impact on costs, a one-year subset of cases with lengths of stay >4 days (n=104) was compared to all available controls (n=1,813) matched on the 3Mtrade mark All Patients Refined Diagnosis Related Group, Version 20, and mortality risk scores. Half of the patients were younger than 65 years, 28% were African American, and 61% had cancer. Median Palliative Performance score was 20 (range, 10-100). Recommendations were implemented in 88% of cases; new "do not resuscitate/do not intubate" orders were written for 34% of patients, new comfort care orders for 44%, and 27% were referred for hospice care. Symptom scores improved from Day 1 to Day 3, with greatest improvement in pain (2.6-1.4, P<0.001). Compared to matched controls without palliative care consultation, palliative care cases had lower cost per day ($897 vs. $1004, P=0.03). Per diem variable costs were 10.7% less for all palliative care cases and 20.5% less for those with >50% hospital days with palliative care consultation. Palliative care consultation is followed by decisions to forego costly treatment and improved symptom scores, and earlier palliative care intervention results in greater cost-savings.