Aim: There is no longitudinal study regarding the changes of insulin resistance (IR) status and the development of complications in type 1 diabetes (T1D). By analyzing data sets from DCCT/EDIC study, we investigated the associations of IR status changes and diabetic complications in T1D. Materials and Methods: Estimated glucose disposal rate (eGDR) was calculated at entry of DCCT and in EDIC year 12 (average 18.5 years later) to represent IR. The participants (n = 957) were divided into four groups based on IR changes from baseline: RR group (stayed resistant; n = 49), RS group (became sensitive; n = 42), SR group (became resistant; n = 197), and SS group (stayed sensitive; n = 669). The association of diabetic complications were analyzed by using multivariable logistic regression models. Results: The improved IR decreased the risk of peripheral neuropathy, whereas the deteriorated IR increased the risk of diabetic complications including hypertension, peripheral artery disease, coronary artery calcification, retinopathy, albuminuria, peripheral neuropathy, and cardiac autonomic neuropathy (P < 0.05). Moreover, RR group (HR = 3.59, 95% CI (2.05–6.32)), RS group (HR = 2.27, 95% CI (1.11–4.64)) and SR group (HR = 1.90, 95% CI (1.24–2.92)) had higher risk of cardiovascular events compared to SS group (P < 0.05). Conclusions: This study highlights the importance of IR changes represented by eGDR in the development of diabetic complications. Patients with T1D and IR may require intensive therapy.