Diabetes mellitus is a disease that affects the way the body produces and uses insulin to control blood sugar. Basal bolus insulin therapy is a combination of short and long acting insulin. But, now a days there is a deadline in this therapy due to the use of automatic insulin pump and continuous glucose monitoring. It reduces A1C without any risk of hypoglycemia. This article review regarding role of basal bolus therapy in diabetes and in depth understanding of DDT including its dose calculation