OBJECTIVES: HIPOS-ER is an observational, cross-sectional, multicenter study to describe the patient population of Type 2 diabetics treated with an anti-hyperglycemic agent (AHA) and admitted to the emergency room (ER) with a hypoglycemic event. In this analysis we aim to identify factors associated with hospitalization following admission in the ER. METHODS: The study enrolled patients from 7 centers in mainland Portugal for a period of 12 months (Jan 2013 – Jan 2014). Sociodemographic and clinical data were collected at the ER and patients who required hospital admission were followed up. Multiple logistic regression was used to identify factors associated with hospitalization.  RESULTS: A total of 238 patients were enrolled of whom 105 (44%) were hospitalized. These patients were older than non-hospitalized (mean: 78 years vs. 75 years; p=0.020). About half of the hospitalized patients were on secretagogue based regimen. Glasgow coma scale score was not statistically different between hospitalized and non-hospitalized patients (p=0.270), however hospital admissions showed lower values of the lowest recorded plasma/capillary glycemia (mean: 35 mg/dL vs. 41 mg/dL; p=0.004) and a higher prevalence of hypoglycemia complications (26% vs. 9%; p<0.001). Obesity and higher plasma capillary glycaemia level are associated with a lower risk of hospitalization (OR=0.29 and OR=0.96, respectively; p<0.010) while treatment with secretagogue based regimen, presence of hypoglycemia complications and other atherosclerotic disease are associated with a higher risk (OR=5.71, OR=3.89 and OR=2.87, respectively; p<0.010). CONCLUSIONS: Almost half of the patients with diabetes suffering a hypoglycemic event who required medical assistance at the ER were hospitalized. Presence of some factors may increase the risk of these expensive cases which are also surrogates for the potential severity of the hypoglycemic episodes. Identification of these predictors may help assist physicians at the emergency room to proactively act upon patients at higher risk of hospitalization and generate substantial health and economic gains to the hospitals.