Heat-related illnesses (HRI) are the most frequent cause of environmental exposure-related injury treated in US emergency departments (ED). While most individuals with HRI evaluated in EDs are discharged to home, understanding predictors of individuals hospitalized with HRI may help public health practitioners and medical providers identify high risk groups who would benefit from educational outreach. We analyzed data collected by the Georgia Department of Public Health, Office of Health Indicators for Planning, regarding ED and hospital discharges for HRI, as identified by ICD-9 codes, between 2002 and 2008 to determine characteristics of individuals receiving care in EDs. Temperature data from CDC's Environmental Public Health Tracking Network were linked to the dataset to determine if ED visits occurred during an extreme heat event (EHE). A multivariable logistic regression model was developed to determine characteristics predicting hospitalization versus ED discharge using demographic characteristics, comorbid conditions, socioeconomic status, the public health district of residence, and the presence of an EHE. Men represented the majority of ED visits (75 %) and hospitalizations (78 %). In the multivariable model, the odds of admission versus ED discharge with an associated HRI increased with age among both men and women, and odds were higher among residents of specific public health districts, particularly in the southern part of the state. Educational efforts targeting the specific risk groups identified by this study may help reduce the burden of hospitalization due to HRI in the state of Georgia.