The prevalence of diabetes is rising globally; currently, 537 million people worldwide and 37.3 million people in the US are affected. Patients with diabetes have a four-times-greater risk of hospitalization with longer hospital stays and a greater chance of readmission compared to patients without diabetes. Spending on diabetes care as a proportion of global GDP is also projected to increase from 1.8% in 2015 to 2.2% in 2030. The largest component of this medical expenditure is inpatient care in hospitalized patients, accounting for USD 69.7 billion of the total medical cost. Hospitalized patients can develop hyperglycemia without a history of pre-existing diabetes. It has been shown that hyperglycemia in patients without a history of diabetes is also associated with poor hospital outcome. In this review, we discuss the adverse effects of hyperglycemia and hypoglycemia on hospital outcomes; we review recent glycemic targets, recent guidelines’ recommendations, and landmark trials with a brief review on discharge planning, updates on hyperglycemic emergencies, and the use of newer technologies in hospitalized patients such as continuous glucose monitoring devices.