Introduction: There is limited literature on the effect of computerized physician order entry (CPOE) on mortality. The objective of our study was to determine if there was a change in mortality among critically ill patients presenting to the emergency department (ED) after the implementation of a CPOE system. Methods: This was a retrospective study of all critically ill patients in the ED during the year before and the year after CPOE implementation. The primary outcome measures were mortality in the ED, after admission, and overall. Secondary outcome measures included length of stay in the resuscitation area of the ED, length of hospital stay, and disposition following hospitalization. Patient disposition was used as a marker for neurologic function, and patients were grouped as either being discharged to home vs. nursing home, rehabilitation center, or a long-term healthcare facility. We analyzed data using descriptive statistics, chi- square, and Wilcoxon rank sum tests. Results: There were 2,974 critically ill patients in the year preceding CPOE and 2,969 patients in the year following CPOE implementation. There were no differences in mortality between the two groups in the ED, after admission, or overall. The pre- and post-CPOE mortality rate for the ED, hospital, or overall was 2.52% vs. 2.02% (P = 0.19, 95% confidence interval [CI] -0.3 to 1.3), 7.8% versus 8.29% (P = 0.61, 95% CI -1.9 to 0.9), and 10.32% vs. 10.31% (P = .60, 95% CI -1.5 to 1.6), respectively. There was no difference in hospital length of stay between pre- and post- CPOE patients (3 days versus 3 days), a difference of 0.05 days (95% CI -0.47 to 0.57). Length of stay in the ED resuscitation area was longer in the post-CPOE group (31 versus 32 minutes), a difference of -1.96 minutes (95% CI -3.4 to -0.53). More patients were discharged to home in the pre-CPOE group (66.8% versus 64.3%), a difference of 2.54% (95% CI 0.13% to 4.96%). Conclusion: The implementation of CPOE was not associated with a change in mortality of critically ill ED patients, but was associated with a decrease in proportion of patients discharged to home after hospitalization.