Background. The Pulmonary Embolism Severity Index (PESI) score can risk-stratify patients with PE but its widespread use is uncertain. With the PESI, we compared length of hospital stay between low, moderate, and high risk PE patients and determined the number of low risk PE patients who were discharged early. Methods. PE patients admitted to St. Joseph Mercy Oakland Hospital from January 2005 to August 2010 were screened. PESI score stratified acute PE patients into low (<85), moderate (86-105), and high (>105) risk categories and their length of hospital stay was compared. Patients with low risk PE discharged early (≤3 days) were calculated. Results. Among 315 PE patients, 51.7% were at low risk. No significant difference in hospital stay between low (7.11 ± 3 d) and moderate (6.88 ± 2.9 d) risk, p > 0.05, as well as low and high risk (7.28 ± 3.0 d), p > 0.05, was found. 9% of low risk patients were discharged ≤ 3 days. Conclusions. There was no significant difference in length of hospital stay between low and high risk groups and only a small number of low risk patients were discharged from the hospital early suggesting that risk tools like PESI may not have a widespread use.