Insulin glargine is used to treat type 1 diabetes (condition in which the body does not produce insulin and therefore cannot control the amount of sugar in the blood). It is also used to treat people with type 2 diabetes (condition in which the body does not use insulin normally and, therefore, cannot control the amount of sugar in the blood) who need insulin to control their diabetes. In people with type 1 diabetes, insulin glargine must be used with another type of insulin (a short-acting insulin). In people with type 2 diabetes, insulin glargine also may be used with another type of insulin or with oral medication(s) for diabetes. Insulin glargine is a long-acting, manmade version of human insulin.