Beta blockers have a proven benefit in the management of patients with acute coronary syndromes (ACS) and for secondary prevention of coronary events. Current guidelines list such reactive airway diseases (RADs) such as asthma and chronic obstructive pulmonary disease as relative contraindications to beta-blocker use. However, the co-morbid burden of RAD and coronary heart disease is substantial, and data suggest that the treatment benefit of beta blockers is shared by patients with RAD. The Get with the Guidelines (GWTG) database was used to evaluate use of beta blockers within 24 hours of admission and at discharge in patients with ACS with (n = 12,967) and without (n = 81,140) a history of RAD. Data were collected in 435 hospitals between January 2000 and September 2006. A multivariable logistic regression model was used to determine predictors of beta-blocker treatment. In patients with no RAD history, beta-blocker prescription rates were 78.3% at admission and 88.7% at discharge; in patients with a RAD history, rates were 65.6% at admission and 77.2% at discharge. Compared with patients with no history of RAD, patients with a history of RAD were 42% less likely (odds ratio 0.58, confidence interval 0.54 to 0.62, p <0.0001) to receive a beta blocker upon admission and 55% less likely (odds ratio 0.45, confidence interval 0.41 to 0.48, p <0.0001) to receive a beta blocker at discharge in multivariable analysis. Among all other clinical factors, RAD history was the most significant predictor of likelihood of not receiving a beta blocker at admission or discharge. Receipt of beta blockers within 24 hours after admission was associated with a lower in-hospital mortality rate for patients with RAD (odds ratio = 0.52, p <0.001) and for patients without RAD (odds ratio = 0.38, p <0.001). Careful assessment of beta-blocker safety and RAD severity by physicians is needed to improve beta-blocker prescription rates in this large group of patients with ACS.