This article is aimed at providing a practical up-to-date review of the precipitating factors, diagnosis, management and secondary prevention of hyperglycemic emergencies (diabetic ketoacidosis (DKA) and hyperglycemic hyperosmolar state (HHS) to assist critical care physicians and hospitalists caring for these patients. Limitations of various guidelines include implementation in settings with an infrastructure different from that specified in the guidelines of a respective country, state, region or community. Appropriate individualized acute management of these conditions typically results in satisfactory clinical outcomes and may decrease the mortality rate from up to 20% in type 2 diabetics with hyperglycemic hyperosmolar state vs less than 2% in patients with DKA. DKA may be the first manifestation of type 1 diabetes and can also occur in type 2 diabetics depending on the state of insulin sufficiency/secretion. For type 1 diabetics, the transition period from adolescence to adulthood is particularly critical to prevent repetitive hospital admissions. Hyperglycemic emergencies are usually preventable but do depend on patient compliance and adherence as well as medical infrastructure. Patients of all ages should be both appropriately educated and assured continuous access to health care to prevent recurrences of these conditions.