The management of type 1 diabetes mellitus (formerly known as insulin-dependent diabetes) has changed dramatically over the past 30 years. In particular, new insulin strategies have improved the ability to maintain near-normal glycemia. Factors such as onset, peak and duration of action can influence the ability of a particular insulin regimen to help control glucose levels. Patient factors, including individual variations in insulin absorption, levels of exercise and types of meals consumed, also influence the effectiveness of an insulin regimen. Rapid-acting insulin lispro is an ideal mealtime insulin. The premeal dose of insulin lispro can be adjusted based on the content of the meal and the patient's blood glucose level. Intermediate-acting and long-acting insulins should not be given to account for the content of a specific meal. Long-acting insulin can be administered once daily at bedtime or, ideally, twice daily in addition to another type of insulin. Patients with type 1 diabetes typically require an insulin dosage of 0.5 to 1.0 unit per kg per day. Newly diagnosed patients may have lower initial requirements because of continued endogenous insulin production. Flexible insulin regimens are based on predetermined actions in response to self-monitoring of blood glucose levels and carbohydrate intake.