Patients with type 2 diabetes mellitus (T2DM) often feature resistance to endogenous and exogenous insulin which is a serious problem to overcome. Current paper presents clinical case of T2DM characterized by marked insulin resistance, where high dosage regimen failed to compensate carbohydrate metabolism. Regarding the case in question we discuss chronic insulin overdosage as one of the possible factors to interfere with compensation of diabetes, as well as capacity of insulin pump therapy to resolve such complicated clinical situation.