Background: Inpatient palliative care consultation (PCC) may reduce 30-day readmissions and inpatient mortality among seriously ill patients. Objective: To evaluate the impact of timing of PCC on 30-day readmissions and inpatient mortality. Design: Retrospective, observational study comparing risk-adjusted, observed-to-expected (O/E) 30-day readmissions and inpatient mortality among patients receiving inpatient PCC to all other inpatients. Setting/Subjects: Adult patients with hospital length of stay (LOS) <30 days, primary diagnoses of circulatory, infectious, respiratory, neoplasms, injury/poisoning, and digestive system were included from eight hospitals in a single health care system. Results: Compared with non-PCC patients (n = 43,463), PCC patients (n = 6043) had a greater proportion of African Americans, Medicare, LOS ‡7 days, intensive care unit stays, discharges to skilled nursing facility and hospice, primary diagnoses of infections and neoplasms, comorbidities of congestive heart failure, cancer, and dementia, Charlson comorbidity score ‡8 (p < 0.001), and fewer males (p = 0.03). Adjusted readmission reduction attributed to PCC among 0-2-, 3-6-, and 7-30-day subgroups was 14.1%, 19.2%, and 16.4%, respectively (usual care O/E = 0.904 vs. subgroup O/Es = 0.764, 0.713, 0.741, respectively). Adjusted mortality reductions attributed to PCC among the 0-2-and 3-6-day subgroups were 19.4% and 19.1%, respectively. A 12% mortality increase was observed in the 7-30-day subgroup (usual care O/E = 0.738 vs. subgroup O/Es = 0.544, 0.547, 0.858, respectively). Conclusions: Inpatient PCC reduces 30-day readmissions and inpatient mortality with the greatest impact demonstrated within six days of hospital admission. Early PCC should be encouraged for eligible patients.