Objectives: to compare healthcare utilization including coronary angiography, percutaneous coronary intervention (PCI), rehospitalization, and rate of subsequent acute myocardial infarction (AMI) within 30 days, among patients presenting to the emergency department (ED) with chest pain admitted as short-term inpatient (≤2 days) versus observation (in-ED observation units combined with in-hospital observation). Methods: We identified adults diagnosed with acute chest pain in the ED from 2010 to 2014 using administrative claims from privately insured and Medicare Advantage. Patients having AMI during the index visit were excluded. One-to-one propensity-score matching and logistic regression were used. Odds ratios (ORs) with 95% confidence intervals (CIs) were reported. Results: A total of 774,017 chest pain visits were included. After matching, healthcare utilization was lower among observation versus short inpatient, with 10.9% versus 24.4% (OR = 0.38, 95% CI = 0.36 to 0.39) undergoing cardiac catheterization and 1.8% versus 7.6% (OR = 0.23, 95% CI = 0.21 to 0.24) having PCI. The incidence of subsequent AMI within the following 30 days was similar in patients admitted as observation versus short inpatient (0.23% vs. 0.21%; OR = 1.09, 95% CI = 0.84 to 1.42). Conclusions: There were higher rates of cardiac catheterization and PCI among those admitted as a short inpatient compared to observation, while the incidence of subsequent AMI within 30 days was similar.